aciam - Nightmare conversion from baquacil to chlorine [Archive]

aciam

06-06-2011, 05:21 PM

Hi pool forum -
I have a 10,000 gal above ground pool with vinyl liner that has used baqaucil since it was built approximately 9-10 years ago. the last few years I have battled haze, at first only at the end of the season, then throughout the season, and last year had a pink algae bloom that was ferocious. I had had enough and decided to convert upon opening this season.

We started the conversion on sat may 29th based on pool store recommendations - but I wasnt happy with the lack of info and explanation they gave me so I researched it on my own and came across your website, which has helped me tremendously. I have been pouring over the site for the last week looking for help and have found lots of information with respect to converting my pool. I ordered the Taylor kit 2006 ( FAS-DPD) ( and had it overnighted to me) and have been using it since wed june 1. The color has slowly changed from a bad green to a very light almost blue green but it is not perfect yet. We never got the thick goo people talked about but did do a lot of vacuuming. Brought pool samples to several stores and laughed at how differently they interpreted the water -so I feel as though I am on my own with this, and I know things aren't quite right.

I don't want to transition to tabs until I am sure the conversion is complete after reading all of your advice but am stuck now and need help. we are on day 10 and the pool still looks a tinge green and the cc levels are through the roof! I feel like I have gone backwards - but am afraid to add too much shock without permission lest I ruin something (like the liner).

so, when we started we were only adding one gallon of shock a day per the pool store recommendations. We did that on sat may 29 thru tues may 31 and then starting on wed my pool testing kit arrived so I can give you more specific numbers.

back on wed I added 1 gal 12.5% shock at 630 am and the FC was 4.4; CC=1.2; since I was told to only put in one gallon a day, I didnt do anymore ( big mistake)

on thurs 6/2 at 10am FC=1.0; cc=.4 ; ph 7.4; alk 80 added 1 gallon 12.5% shock then tested at 2pm FC was 2.7 and CC was 0.8 so added another gallon of shock (12.5%) ( after having read your site i wised up to the process); tested again at 4pm and FC was 7.4; CC was 6! started getting worried but added another gallon 12.5% shock anyways.

fri 6/3 - at 8am FC was 10.5 and CC 3 no bleach added; 3pm FC 5.5 and CC 1.0 - thought I was making progress so added 2 gallons of 12.5% bleach ( ie shock) to try to move things along.

sat 6/4 11 am FC 11.5 and CC 6.5! ph 7.6 alk 90 ( I repeated these numbers as well using 10ml and 25ml volumes just to check myself.) no bleach added; the pool was still very cloudy so I added 2oz of a 4 in 1 clarifier; 4pm FC 9 and CC 2.5 - added 1 gallon 12.5% bleach. then at 9 pm FC was 11 but CC was 8.0!!!! I was starting to get discouraged - but added a gallon of the bleach 12.5% and went to bed.

sun 6/5 9am FC 12 and CC was 14!!! I added nothing because I was afraid the total chlorine was too high. retested at 130pm fc was 11 and CC was 8.5 - added nothing - retested at 9pm and FC was 9.5 and CC was 5 - added 1 gallon 12.5% bleach and went to bed very confused.

this morning the pool looks a bit more blue and is crystal clear but still a green hue ( we did change the sand yesterday for time reasons with the upcoming week very busy)
FC 11.5 and CC 12.

I haven't added anything today and was waiting for advice before i retested or added more bleach. I have read a lot about chloramine and the CC and I just am not sure what to do now to get it to go down -- I think I might have created more by not being aggressive enough with the shock. the pool is looking better but the testing is not moving in the right direction. Could it be an error? How high can the total chlorine go? what should my next step be?
Thank you so much for you help. aciam

aylad

06-06-2011, 05:59 PM

You need to be a little more aggressive with the chlorine--looks like you're adding enough to start killing the old Baq off, but not enough to get ahead of it. With zero stabilizer in the water, you need to add enough chlorine to get to 12-15 ppm and do your best to hold it there as consistently as possible. If you can test/add additional chlorine 2-3 or more times daily, that's even better. If you can hold it at that "shock" level, you will win the battle--you just need to bump it up a little. Also, no more clarifiers or anything else except chlorine. Everything extra that you add is adding to your chlorine demand, and you already are barely keeping enough in the pool for the Baq. So..nothing else extra.

In a 10K gallon pool, one gallon of 12.5% chlorine raises your chlorine to 12.5 ppm--IF your chlorine is still full strength, which it may or may not be. Add your chlorine, give it 30-40 minutes to circulate, and retest--and bump it up if you need to til you're between the 12-15 ppm mark--then test and re-add as often as you can. It'll work!!

Janet

aciam

06-06-2011, 06:32 PM

Thanks Janet - do you mean keep FC 12-15ppm and not worry so much about the total chlorine level ( the FC added to my CC level)? because those seem kind of high lately. will i bleach out my liner or is that not true? I am surprised by how high my cc levels were getting - and it is now day 10 of the conversion. What does that mean? I remember reading somewhere on the forum that you can raise cc levels by inadequate shocking. Am i making it all worse by adding too little? Thanks. aciam

Watermom

06-06-2011, 06:51 PM

Janet has given you good advice. While you are converting, your high chlorine levels won't last for long. They will quickly drop as part of the conversion process. The more consistently you maintain the chlorine levels between 12-15, the faster your conversion will go. As many times a day as you can test and add enough bleach to get back to 12-15, do it. No such thing as doing it too often. Keep us posted how things are going!

aciam

06-07-2011, 11:27 AM

I was hoping to get some more advice about how to proceed at this point. so, I added no bleach all day yesterday - the morning readings were 11.5 FC and 12 for CC ( yikes) - after reading your advice I retested at 7pm and the FC was 9 and the CC 4.5. I then added 1/2 gallong bleach (12.5%) and retested at 830pm - the FC was only up to 10 and the CC was approximately 9!!! I ran out of the titrating reagent for my kit at this point.

I figured all the bleach I added pretty much got combined with that high of a reading. So, I decided to add 1 more gallon of bleach for overnight work in a desperate attempt to kill off the combined chlorine. Not sure if that was correct.

I decided to head to the pool store this am to get the water tested since I couldnt do it here and realized that they cant test above 5ppm with their in store test! The guy made me feel really badly about having so much chlorine in the pool - he said he had never seen the color turn so deep pink/red and guesstimated a free chlorine of 7 and total chlorine of 9. I bought some test strips that check total and free chlorine myself just as a way to get through today without my testing kit up and running - they test up to 10ppm - and both pads hit that mark ( for FC and TC). Problem is I don't know where I am in terms of my CC and what to do today in terms of adding bleach now.

The pool store guy made me feel so badly I practically ran out of the store. He suggested non chlorine oxidizer - and told me that if I put clothes in the pool right now they would bleach out immediately. I'm hoping you guys can make me feel better about what I am doing because I feel like things are getting worse in terms of my CC instead of better. I am now on day 11 of this process. The pool looks really great today - clear and blue and of course the weather is supposed to be in the high 90's the next several days - and my kids are dying to swim.

so, here are my questions. Why does the CC keep climbing so incredibly high? the sand is changed and clean and has no residual baquacil in it and my baquacil readings on day 6 were 0.

Is it the free chlorine I am supposed to keep at 12-15? what about the total being so high?

I noticed my chlorine is maintaining itself throughout the day despite sun ( yesterdays readings of 11.5 in the am to 9 in pm with no added bleach) doesn't that seem like a good thing? like I am ready to let it drop to levels we can swim in? ( my kids so want to swim)

what do I do today since I have no good way to test for CC?

Thanks so much. aciam

CarlD

06-07-2011, 12:01 PM

Either of 2 things is going on: You still have a lot of conversion yet to do, or you are running the test incorrectly.

Meantime, order more of the reagents on-line. If somehow, by a miracle the pool store guy is right and your FC was 7 and TC was 9, that means your CC was 2. Remember TC = FC + CC. Always.

Plus the test strips' TC block is never very accurate. the FC block is better. You can dilute a sample of pool water with steam distilled water 1:1 and then use the strip. If it reads "10" your FC is 20, or double. Again your TC is probably not going to make sense. But if you remember that TC MUST be greater than or equal to FC, you'll realize the TC test on the strips isn't very good.

I "cheat" and use strips to get a quick idea of my water, but I've been using the FAS-DPD tests for SO many years, as well as the OTO tests, that I can easily verify with the FAS-DPD test that the FC pad on the strip is reasonably accurate, but the TC pad is garbage.

Now remember that you must keep your FC level at the recommended shocking level (based on your stabilizer level) until your pool is COMPLETELY clear and you get no CC reading (at least not higher than 0.5ppm). Then you can back off your chlorine levels, adjust your other readings, and replace the now-gooped-up sand in your filter.

All the best,

Carl

aciam

06-07-2011, 12:21 PM

I know the pool guy was just guessing because his test didn't go higher than 5ppm. I think my test strip pad is more accurate and that the FC is probably 10 or a bit higher. But I have no idea what my CC is. Oh and the sand was changed 2 days ago which is why I am so confused as to why the CC is still so high - there is no residual baquacil to react with. I also have no stabilizer in yet as per the conversion instructions - waiting to get things set straight before I do that. I'm pretty sure I am doing the test correctly. But in all my reading I have never seen CC levels as high as mine which is worrisome to me. would love some reassurance.

so I guess today I will just try to keep the FC up at 12-15 by my pad tests - the new reagents were already ordered and should be here tomorrow and then I can regroup.

Any answers to my other questions from the previous post? Thanks! aciam

aylad

06-07-2011, 06:45 PM

so, here are my questions. Why does the CC keep climbing so incredibly high? the sand is changed and clean and has no residual baquacil in it and my baquacil readings on day 6 were 0.

Is it the free chlorine I am supposed to keep at 12-15? what about the total being so high?

The CC is climbing high because the chlorine is still trying to kill off something in the water, probably leftover residual from the Baq and other Baq products. If you changed the sand before all the Baq goo was gone, then you probably do still have some in the filter and will need to change the sand again, once it's all gone. We normally recommend that you get to the point of no CC and holding chlorine overnight before sand changes, and that is why.

Yes, the FC needs to be 12-15 ppm in order to kill off whatever is causing your CC. If you keep the chlorine up, the CC will eventually come down and the gunk is removed from your pool. Sometimes it just takes a lot of patience, persistence, and being very diligent about keeping the chlorine high.

Janet

aciam

06-09-2011, 02:12 PM

OK guys - I just got my new titrating reagent today and I am getting some scary numbers on the test. After adding bleach, my CC has climbed to 25 with a FC of 15. It has been 2 weeks since I started the conversion - I had much lower levels of CC the first week. the pool is crystal clear but my hands hurt after getting a water sample! What am I doing wrong?

Watermom

06-09-2011, 03:16 PM

Try that test again. I'm pretty sure those numbers can't be right.

PoolDoc

06-09-2011, 08:49 PM

Go purchase a cheap OTO test kit, and see what color you get, please.

I'm concerned about what's happening. I emailed you my phone number.

Ben

Watermom

06-09-2011, 11:25 PM

Ben,
Please come back and update this thread and let us know what's up with this pool after you talk with this poster.

PoolDoc

06-10-2011, 03:41 PM

These two threads:

http://www.poolforum.com/pf2/showthread.php?11734-Chlorine-Locked
http://www.poolforum.com/pf2/showthread.php?11784-first-post-aciam-converting-pool-from-baquacil-to-chlorine
seem to be both products of an issue I don't remember dealing with before: pools with a LONG history of Baquacil use, before conversion.

I talked with "Aciam" at length last night, and agreed upon the following:

#1 - Test with OTO ; ignore FC / CC differientiation
#2 - Dose to dark yellow (~10ppm); allow it to drop to medium yellow (~2 ppm)
#3 - Continue filtering 24/7
(Aciam's water is clear, but some sort of surface debris is forming continuously and being collected on her skimmer sox)
#4 - Dose with polyquat that the FIRST signs of algae (slippery sides on Aciam's vinyl AG pool)
#5 - If no resolution after a few days, consider drain and refill (AG pools ONLY!)

My **guess** is that there's a huge accumulation of Baqua-goo from the years of Baquacil use, and that -- whatever else Baqua-goo is, chemically speaking -- it is very resistant to chlorine oxidation. The high CC levels are a result of slow (but sure) oxidation by chlorine.

What's weird is that her FAS-DPD readings did NOT match her OTO test results at all. I trust OTO more than DPD, so I made the recommendation above. However, I had to tell her I really have no idea how cleanup will take. I've emailed Chem_Geek to see if he's collected any info on this.

Ben

PoolDoc

06-11-2011, 07:39 AM

This is what I posted in the other thread -- but it applies here, too. It's amazing that, having never encountered this here before, we have two simultaneous cases!

Ben

PS. Just found a study of the biodegradation of PHMB. One implication is that, if you let your pool go swampy for a few weeks, bacterial biodegradation of the Baqua-Poop may occur. If you were to try this, and have any of your old filter sand around, you might want to toss some in the pool AFTER the chlorine is gone. Apparently PHMB-eating bacteria accumulate in the filters of PHMB treated swimming pools!

================================================

Hi Reesie;

Just heard from Chem_Geek. He's seen some similar situations on other forums he frequents -- and as best he can tell, the situation is just what I guessed.

You've used Baquacil for years, and have years of "Baqua-poop" or residue from Baquacil in your pool. This stuff is HARDER to break down then Baquacil itself. Apparently, it can take up to 6 weeks to complete the conversion. Richard (Chem_Geek) thinks using sodium percarbonate doses might help, but this is a bit of a guess, too.

Here are links, if you want to try that:
http://www.chemistrystore.com/Sodium_Percarbonate-Sodium_Percarbonate_30lbs.html
http://www.soapgoods.com/Sodium-Percarbonate-FB-p-1001.html

The bad news is, I don't think it's safe to swim while your CC levels are so how. If you read aciam's thread, you'll see it hurt her hands to just stick them in the water.

The really bad news is, I can't tell you much of anything definite:
+ Nobody who knows just what "Baqua-poop" (residue from Baquacil use) is is talking or publishing. ICI Americas, who patented the product, probably knows. But they haven't made that info available.
+ So . . . nobody knows what's forming when chlorine breaks Baqua-poop down. Observation (test, smell) indicates that it's some sort of noxious chloramine.
+ And, since nobody knows what it is, nobody is sure how to go about breaking it down faster.
+ Worse, this is such an uncommon event, that nobody has good guidelines to offer you.

Your options:
#1 - Keep chlorinating. It will eventually break down and go away, but it may take weeks more.
#2 - Buy sodium percarbonate and add that, too. (Let us help you with the doses if you do this)
#3 - Add copper sulfate. Copper sulfate (a pool algaecide) breaks down Baquacil; it may break down Baqua-Poop. It probably won't make anything worse. You may be able to get it at Lowes as "Root destroyer" in the plumbing section; you can buy it from the chemistry store link. Again, let me help you with doses if you do this.
#4 - Drain and refill.

I wish I had better news for your.

Ben
================================================

aciam

06-11-2011, 12:28 PM

Hi Ben -

thank you for that information. Let me update you on my pool these last 36 hours since we spoke.

On Fri 6/10 at 8am the TC by OTO was >5 as indicated by a brighter yellow than the color on the top most cell. It did not turn orange or brown despite sitting for a while. Out of curiosity(and despite your advice) I tested with my FAS-DPD kit and got a FC of 9 and CC 22.5 ( is the OTO not picking up the weird chloramine that is being created by the baquagoop?)

at 2pm the TC by OTO was again >5 (fc 7.5 and CC 12.5) I added no bleach.

This morning sat 6/11 at 8am the total chlorine by OTO was still >5 but slightly less bright yellow than yesterday I think. (FC 5.5 and CC 5.5)

I have added no bleach since thursday the 9th.

I tested my hypothesis that I had a defective kit/reagents by doing the FAS-DPD on a sample of bleach water that I made up in the kitchen and of course I got a perfectly fine FC reading and a nonexistent CC - so there goes that hypothesis!

A lot of what you are saying makes sense as I review the numbers over the last few days - every time I have added bleach the FC rises a small amount but the CC rises a huge amount - supporting the theory that some weird chemical reaction is occurring to convert the fresh bleach not into free chlorine but some noxious chloramine substance. And it is slow to breakdown as evidence by how slowly my numbers are dropping despite no bleach added in 2 days.

what's weird is that the total chlorine level does not reflect the FAS-DPD total numbers - is it that the OTO can't pick up this new chloramine? Maybe it doesn't matter for swimming????

As you can imagine, none of the options you present seem particularly appealing ( not your fault :). Do you know that the sodium percarbonate or copper sulfate will actually work or is that just a guess? I need to mull it all over and talk about it with my husband before deciding our next step.

But let me present this question to you - what is the problem with letting both the CC and FC drop to low levels like around 1-3 - and swimming in the pool over the summer. If I can maintain the FC at an appropriate sanitizing level, and keep the CC low enough so it is not totally offensive, can we just use it while the process of eating up the baquacil just continues over the summer? The pool is crystal clear and blue and so inviting!

My husband asks why, if we can swim in lakes and ponds that have such offensive materials in them, not swim in this pool? Any takers for that one???

I will continue to monitor the pool per your advice and not add bleach now. And then if we decide on the 2 new chemicals you suggested I will post with advice on doses.

Thank you again for all your help. aciam

waterbear

06-11-2011, 06:06 PM

The sodium percarbonate will oxidize the biguanide and goo in your pool. However, it will also destroy any chlorine and chloramines present since it creates hydrogen peroxide when dissolved. Therefore, you might need to dose two or three times with the percarbonate for it to be effective if you have high levels of combined chlorine presently. The first applicaton with get used up destroying the chlorine compounds and subsequent applications can then attack the biguanide and residue in the pool.
Normal dosing is 1 lb per 1000 gallon water and since it will cause the pH to rise the addition of 3/4 lb of dry acid for every 1 lb of percarbonate added will keep the pH in line. So for a 10k gallon pool you would need 10 lbs of percarbonate and about 7 lbs of dry acid for each dose. Turn off the pump and broadcast the perscarbonate on the water surface then immediately broadcast the dry acid. The stuff may 'fizz' and cause gunk to float to the surface.
Skim out as much of this as possible then turn on the pump and filter 24/7 for 48 hours. You should have no or little chlorine in the pool at this point and should clean the filter and repeat the process again.
If the water is not clear after another 48 hours of filtration repeat again.

Some people do not add the dry acid initially and let the percarbonate work at the higher pH then lower the pH after the conversion I do not personally know which method is more effective but do know that it does work either way.

At this point what little biguanide remains in the water and filter should be easily oxidized by chlorine if any is left so add chlorine and see how much CC is present or if the water turns colors when you add the chlorine. Once conversion is complete change out your filer medium, be it sand, cartridge, or DE. NO simple backwash here. Break down the filer and clean and soak everything. Repalce the sand, carts or DE completely.

Do not swim in the pool until conversion is compete. The water can be irritating to say the least!

PoolDoc

06-11-2011, 11:00 PM

Hi Aciam;

Waterbear has described the percarbonate method above, but your situation is somewhat unique. I've never used that method, and am a bit skeptical. (Waterbear, you say percarbonate releases peroxide. But if so, how does that help? Baquacil Shok is very strong peroxide.)

Chem_Geek is confident that percarbonate will work FASTER in a regular conversion of PHMB, but your PHMB is already gone; what's left is 'Baqua-poop' or degraded Baquacil. Chem_Geek is NOT sure that percarbonate will work better (or even at all) against Baqua-poop.

Do I know whether copper or copper + silver or copper + silver + monopersulfate will work? No, not at all. I'm pretty sure that chlorine will work eventually, but I can't give you any time frame. There have been references to similar situations, but I haven't been able to find them, and to such conversions taking 6 weeks, but I don't know!

But, I completely agree with Waterbear on swimming: this is NOT like swimming in a dirty lake. Ordinary chloramines can be very irritating to skin and the genitals. I don't know what is in your pool, but as you already noted, it hurt your hand.

Sorry I have so little info. I spent 3 hours on research this afternoon, and only found out how much is NOT known.

Ben

waterbear

06-11-2011, 11:35 PM

Baquacil Shok is very strong peroxide.

Stabilized with citric acid and with a low pH. The percarbonate will be at normal pool pH if the acid is added or quite alkaline if it is not. While I have no data as to which is more effective I suspect the pH plays and important role here and that NOT adding the acid until after the conversion is the more effective route since stabilized 27% peroxide does not appear to destroy biguanide to any great extent, nor does MPS, which is also acidic. I have also seen patent data that indicates that sodium persulfate, which is also normally acidic, does not degrade biguanide to any great extent but at high pH it does.

aciam

06-12-2011, 05:47 PM

Thank you both for thinking so hard about my pool. I have also been thinking hard and wanted to post something that may or may not be helpful. 1-2 years ago Baquacil developed a CDX system – to enhance oxidation. The instructions were for weekly maintenance - to poor the weekly dose of oxidizer ( 27% H2O2) in front of the skimmer followed by “CDX” into the skimmer which was supposed to help maintain the oxidizer residual. The ingredients are a combination of dimethyl and hydroxymethyl hydantoin. We used this system for the last 1 -2 years – and before that used oxidizer increaser tablets in the skimmer basket to battle the constant haze problem. I can get those ingredients as well if you think it might be helpful. But I post this info in case it might shed some light as to why my pool is behaving so differently and in case this chemical is potentially the culprit in creating the noxious chloramines?

I had meant to ask also if using a non chlorine shock might have a role at this point in my pool – but the percarbonate method sounds like it may be doing just that – oxidizing without chlorine? But thought I would ask since the non chlorine shock seems less time intensive, has less side effects, and is more readily available. I was thinking about whether I should add some chlorine to raise the CC levels, and then hit it with the non chlorine shock to kill them all off – I have no experience whatsoever on which to base this thought except of course the wracking of my brain to find a solution. Hoping you all could comment on it since you have the experience to back up your recommendations :)

In the way of an update, this morning at 1030 am my TC by OTO was just slightly more yellow than the 5 cell. pH was 7.5
FC was 5.5 and CC was 2 by FAS-DPD testing

At 4:30 the TC by OTO was less yellow than 5 but more yellow than 3 so I called it a 4
FC was 5 and CC was <0.5!!!! for the first time ever with a much less strong bleach smell than in the past.

My thought was to see what it did overnight – since the FC has held at five now for 36 hours and I haven’t added bleach in over 3 days – and re test in the morning. I want to see what happens when I add more bleach in terms of raising the CC levels again. I expect that it will raise the CC more than the FC if this process is still going on. I will be happily surprised if it does not – because that will mean this nightmare is over and we could actually swim in the pool! But it is rainy and cold here right now so we don’t feel too badly about missing out on the pool. Safety is our first concern. After I perform my little experiment to test my hypothesis I have no idea what I will do next - but may run it by you all! I am taking it one day at a time with this pool. Thanks again. aciam

chem geek

06-13-2011, 04:28 AM

waterbear

06-13-2011, 10:59 AM

FYI. The procedure is in this PDF file (http://piscines-apollo.com/docs/baquacil_to_chlorine_conversion.pdf) (OXYplus™ is sodium percarbonate). The dosage was 5 pounds per 10,000 gallons (so 1 pound per 2000 gallons) which is less than the dosage normally recommended for ProTeam® System Support (but the purpose is different here) -- note that this is different than I wrote to Ben earlier since I found a reference to Orenda's instructions. Also, I thought that it was added without the acid and that after the conversion then acid was added to adjust pH as needed.
Thanks Richard, I was looking for Dick Kersey's instructions and couldn't find them! I thought his dosing was half that of Proteams' but could not remember. I had lost contact with him when he moved and started his newest product line selling phosphate removes and enzymes. Remember that this is the same person who gave us the ill fated CYA reducer that does not seem to be on the market anymore. I do know that he recommended adjusting pH after conversion so he is doing it in a high pH environment but I have also personally know of conversions that were successful using the higher dosing and keeping the pH at normal levels. However, the addition of hydantions to the water (Baquacil CDX) certainly is part of the problem here. We know the effect that hydantoins have on bromine (and chlorine for that matter) and it seems that they have a similar effect to stabilize hydrogen peroxide because they are an aldehyde doner (same reason they are used as preservatives in cosmetics and shampoos). If this is the case then a drain and refill might be the only way to solve this problem unless there is some way to break down the hydantion compounds in the water.

aciam

06-13-2011, 02:20 PM

Can you explain how hydantoins work on chlorine to me? Just so I understand.

I tested my hypothesis again today - this morning at 730 am numbers were TC by OTO of appromimately 5 with FC of 4 and CC 1; at noon TC by OTO was closer to 3 with FC of 3 and CC of 1 by DPD-FAS so I decided to add approximately 1/2 gal 12.5% bleach - and retested one hour later at 1 pm. ( 10k gallon above ground pool)

Here are the results: TC by OTO = approximately 5
FC 5; CC now 6

Clearly the new bleach is being routed to CC despite no one using the pool - just as I have seen over the past 2 weeks with each addition of fresh chlorine - and evidenced by little rise in the free chlorine. And also I think it seems out of the norm that my chlorine levels are so stable - for days even - without any new bleach or stabilizer at all. Something is stabilizing it and I imagine trying to maintain a pool in this state would be impossible.

I did find one other person on a different pool site who was experiencing similar problems - as you all had mentioned before - but he stopped posting and so there is no follow up. I wonder if he or reesie used the CDX system? there has got to be a group of people who used this system and are now trying to convert - so I am sure this problem has to be coming up - although if everyone only listened to the pool store, no one would be testing CC and people would be using their pools once they were clear not aware of the problem.

Now that we know about the hydantoins, does that change all of your minds about the benefit of the percarbonate and was it copper sulfate additions? This is an above ground pool - how risky is a drain refill? would it have to be fully drained or could a foot of water remain? would that leave enough hydantoin circulating in the fresh water to continue to cause problems?

I would rather pay someone to come and oversee the drain and refill to make sure it was done in the best way - (any of you want to fly up to good old massachusetts?????? ) But it sounds like there still is a risk of damaging the pool? I need to find someone good and someone who will understand why we are doing this. That will not be an easy task!

In the meantime - the good news is that I don't have to keep checking the pool that often because the chlorine is nice and stable! But I'm not sure if it is worth it to keep adding bleach - it seems like nothing is better from 2 weeks ago. I will wait to hear back from you all. aciam

waterbear

06-13-2011, 02:46 PM

I still think the percarbonate is worth a shot. It is a strong oxidizer and it's worth the experiment. If it does not work you are out the price of the percarbonate, which is not that expensive. If it works you have added to our combined knowledge of pool chemistry if you are willing to do so. I have been researching online to see what I can find out about stablizaiton of peroxide by methylated hydantions and also any possible effects on biguanide (there is some indication that it may introduce additional polymerization but nothing specific that I can find so far.)

Methylated Hydantions are used to stabilize bromine and some chlorine disinfecting compounds so the sanitizer is release slowly but they have no effect on protection from UV so they are not commonly used in chlorine products for pool. If I am not mistaken the chlorinated hydantoins will test as combined chlorine but will still slowly release hypochlorous acid. (Ben, Chem Geek any info on this? What I have been able to find is really spotty and I have had to read between the lines a bit, so to speak.)
The old adage that 'bromine is forever' is true when the bromine source is from either BDCMH or DBDMH (the two most commmon bromine tabs used in pools and spas) because the DMH keeps the bromide from oxidizing to bromate and therefore to convert to chlorine you must drain and refill. When inorganic bromine is used (sodium bromide) the continual addition of chlorine and the effect of sunlight will effectively destroy the bromide ions so the cannot regenerate bromine sanitizer and the pool or spa converts back to a chlorine system again as long as more sodium bromide is not added.

If I find out anything else I will post it!

madwil

06-13-2011, 02:54 PM

Been a long time since chemistry classes- but the reduction chain for hydantions looks problematic. Like waterbear said, the cheap test may work, and will give us all some data for future use.
I've been trying to reach an old buddy of mine, who works at water treatment plant (with hydantion type slow-release chlorine that waterbear mentioned) to see what they do to remove it after treating the water system- may give us a clue to pools, or may only be practical in industrial environment... problem is I've been out of touch with them for 20 years, since I joined the Navy!

chem geek

06-13-2011, 03:51 PM

This MSDS (http://www.leisurepoolinc.com/sitebuildercontent/sitebuilderfiles/CDX85025.pdf) shows that Baquacil CDX is 5,5-dimethylhydantoin (DMH). I can't find equilibrium constants on bromine with DMH nor chlorine with DMH. There are numerous warning-like recommendations for a DMH maximum of 200 ppm as noted in links in this post (http://www.poolspaforum.com/forum/index.php?showtopic=26699&st=0&p=118675&#entry118675). It seems that bromine and DMH may be like chlorine and CYA where some or perhaps much of the bromine attaches to DMH. You mentioned that this did not protect bromine from sunlight, but it might help somewhat by reducing hypobromous acid concentration though not as much as CYA which has an additional UV-shielding effect. Anyway, the real question is whether there is enough chlorine that binds to DMH to report as CC. I find this unlikely since BCDMH tablets wouldn't work properly if the chlorine remained tightly bound to DMH. Though there might be an equilibrium, if it were fast enough then that would show up as FC just as it does for chlorine bound to CYA. On the other hand, DMH is the most likely candidate from what we've been looking at for the persistent CC so maybe when DMH concentrations are very high that the chlorine indeed binds to it strongly enough to measure as CC -- I really don't know. Maybe the release is slow in which case one could test for FC and wait -- if the FC continues to climb and then stops then test CC. If this time isn't too long, then this could confirm chlorine attached to DMH getting slowly released though it is already know that there is some bleed-through of CC into the FC test if one waits too long.

As for why DMH is added, it is interesting that in this link (http://www.h2o2.com/faqs/FaqDetail.aspx?fId=42) dimethylhydantoin is not listed as a stabilizer for hydrogen peroxide. It sounds more like DMH is used to help stabilize hydrogen peroxide against breakdown from sunlight. This link (http://www.epa.gov/hpv/pubs/summaries/55dmth/c14589.pdf) gives some info from the EPA on DMH where photo-degradation is noted, BUT in the atmosphere with hydroxyl radicals with a half-life of 3-1/2 days for their assumptions. This may mean that having FC in the water along with sunlight MAY help degrade DMH due to production of hydroxyl radicals, but from what we've seen in these pools it seems that this is too slow. On PDF page 38 they talk about aqueous photolysis with a half-life of 878 days (other tests described later have even longer half-lives) so clearly sunlight alone without chlorine would not be enough to degrade DMH quickly. It does biodegrade in sludge (i.e. bacterial degradation).

aciam

06-13-2011, 10:53 PM

So I have read chem Geek’s last post several times to make sure I am understanding it – and wanted to present a data point from last Thursday that might shed some light on what you were thinking in terms of equilibrium of DMH and chlorine release – I have not ever done the FC CC tests on a single sample waiting 10 or 20 minutes in between tests – BUT I do have some data from multiple tests close in time after adding bleach.

Last wed I dumped a lot of bleach into the pool desperately trying to get my FC to 12-15 which was the level recommended to me on this thread – I had no more titrating reagent and was relying on “cheap” kits – the OTO for TC and DPD for FC by color matching. I could never get to 12-15 despite all the bleach I was adding – but in retrospect I now can see why. So once I got my new reagent in the mail I decided to test at multiple points after adding bleach to see what was happening to the bleach in the pool – this is when I first noted that all the bleach was combining with something to increase my CC incredibly high but only raising the FC a minimal amount.

So, last Thursday at 1pm I tested with my new reagents and got a FC =8 and CC=16

I added 1 and ½ gallons of 12.5 % bleach at 1:20pm – which should have raised the chlorine level by approximately 15 -18?? Is that right?

I tested 20 minutes later ( at 1:40) FC=11.5 ( slight inc) and CC=35 (huge increase)

I retested (a new pool sample) 20 minutes later again ( 2pm) FC=15 (now higher) and CC=25 (now lower)

After that the testing shows both numbers slowly decreasing.

I present this in case it helps to clarify your thought process – that in fact the new bleach being added seems to be primarily binding to something (the DMH presumably) right away and testing out as CC – and then slowly dissociates to increase free chlorine levels and decrease CC but only to a point. I don’t know what is governing that dissociation equilibrium. Nor is there any real consistency to the numbers – some days the CC can be high without even adding any new bleach.

I haven’t done any other testing so closely in time to adding bleach so have no other data points to present.

What I do know is that it is nearly impossible to achieve high levels of FC in this pool without pouring in huge amounts of chlorine thus causing the CC to skyrocket – and the CC levels seem to stay in the lower range when there is less free chlorine measured.

SO I guess the question is can we break down the hydantoins in any effective way to change the chemistry of the pool so it works properly. I am curious to see if madwil gets any information from his buddy at the water plant - that might give us some insight into whether anything we do could actually breakdown these substances. And whether I really need to seriously consider a drain and refill.

Then if we decide to try the percarbonate – I suppose I will need everyone’s consensus on how to do it – 1 pound or 2 per 1000gal – acid or no acid. I’m not sure I was clear on the final recommendation. Perhaps that’s because none of you are either ☺

I feel like I am back in my organic chemistry class in college – and let me tell you all – I did not like organic chemistry!!!! It is like a nightmare that has come to haunt me all these years later……..My husband just shakes his head at me when he ventures down to the basement to see me with all my bottles and reagents. It is kind of comical. If I wasn’t so upset about all of this, I’d really have to laugh at it. Maybe after this is all done I will. Thank you for all of your help. aciam

chem geek

06-14-2011, 12:16 AM

According to the Orenda instructions, it's 1 pound per 2000 gallons (5 pounds per 10,000 gallons) without adding acid until you are done with the conversion.

Note this post (http://www.troublefreepool.com/truly-trouble-free-baquacil-conversion-t33684.html#p275338) where there might be a slow drop in CC over time.

You could do a bucket test for the percarbonate rather subjecting your entire pool to it. If it works for pool water in a bucket, it should work in the pool. You'd scale down to very small added quantities as a result. 0.016 ounces weight (somewhat less than 1/8th of a teaspoon, I think) of sodium percarbonate in 2 gallons.

reesie

06-15-2011, 08:32 PM

Hi aciam,
It's reesie. Yes, I used CDX the last 1 or 2 years ( I think 2 years) and the tablets the year before just like you. I didn't realize it was going to come back to haunt me!

chem geek

06-15-2011, 09:59 PM

FYI. This patent (http://www.google.com/patents/about?id=9RwRAAAAEBAJ&dq=%22richard+sinden%22&num=4&client=internal-uds&source=uds) talks about using various aldehyde donors (as Evan mentioned) including DMH equilibrium compounds in water to stabilize hydrogen peroxide though that stabilization is described as preventing too much reaction from decomposing enyzmes often found in some organic matter (such as recycled paper). They don't mention stabilization with respect to sunlight. Anyway, I'm going to see if most of the conversions at TFP that went well didn't use CDX. The same should be checked here as well if possible.

aciam

06-19-2011, 03:15 PM

Hi Chem geek - so the sodium percarbonate has arrived - we had a medical emergency in the family so I have had to put the pool stuff on the back burner - I am hoping to try the bucket test sometime in the next few days using 1/8th tsp of Na percarbonate in 2 gallons per your instructions but just need guidance as to what I am looking for and how long to wait before I retest the bucket water. And how I will know it has worked - or if I need to repeat the dose and retest in a certain time frame. Thanks. aciam

waterbear

06-19-2011, 05:33 PM

I would do it like this:
sprinkle it on the surface of the water and let it sit for 48 hours, stirring every so often. Then add 1/4 teaspoon 6% bleach (this should raise the FC by approx 20 ppm), stir, and test with OTO, it should be dark yellow orange to brown if the chloirne is holding (percarbonate destroys chlorine and vice versa but after 48 hours I would think it was all used up) . IF it is still very pale yellow or clear add another 1/4 teaspoon bleach. When the bucket is holding chlorine. test with FAS-DPD and see if the CC problem has been solved (HIgh FC, little or not CC). Let it sit an hour or two and test again to make sure CC has not climbed like it has been.

If your test results are better than before the percarbonate it is probably worth a try. Like I said before it might take two or three applications. so If the first time is a no go repeat the percarbonate on the same bucket of water and see if two ( or even three applications) do the trick (wait for the chlorine to drop low first...a few hours of sunlight should do it). If so just add your dose to the pool every 48 hours with pump off, skim, and fitler for 48 hours then shock with chloirne and test.

Chen geek might have another way to do this.

chem geek

06-19-2011, 07:07 PM

I think what waterbear described is a good approach.

aciam

06-22-2011, 09:48 PM

Hi guys - so I read Reesie's thread and was excited about her positive results. I started my bucket test at 3pm yesterday 6/21 and decided to follow her protocol. The water tested at FC=4 CC=20 ( I had put in 2 gallons of shock over the day trying to get my FC up but as you can see all it did was raise my CC) prior to adding 1/8 tsp of sodium percarbonate

6/21 : 8 hours later I tested the bucket ( 11pm) FC=0 CC= 6 repeat test 8
6/22: this morning 830 am (17 1/2hours in bucket) FC=0 CC 6
930 pm ( 30 1/2 hours in bucket) FC=0 CC 8

of note: I forgot to rinse the vial after this mornings test and when I arrived home from work the liquid had turned a deep purple
Also, I am finding that the water is only turning a light pink once the second reagent is added ( for the CC) but is very very resistant to being titrated to clear - and upon sitting after the test is done, starts to turn pink again.
Any ideas as to what this means?

Since I feel like I have hit a wall, I decided to add another 1/8 tsp of the percarbonate to my bucket to see if it will oxidize out the CC for I feel like I can't go further with this experiment and add bleach if I can't even get the CC to go away. Was that OK? any other advice? aciam

chem geek

06-22-2011, 09:50 PM

Yes, I think it's OK for you to hit with more sodium percarbonate to see if that lowers the CC further. At least going from 20 to 8 was a good positive step and you did the right thing not to add the bleach yet since you were still measuring CC. Your situation may be more extreme than Reesie's. Keep us posted.

waterbear

06-22-2011, 11:14 PM

Like I said before, it may take two or three "treatments" with percarbonate before you oxidize all the 'goo' in the water.

aciam

06-23-2011, 09:56 AM

Hi guys - so my news is disappointing this morning. My test on the bucket water was FC=0 CC=35 but I have to tell you the titrating is really weird so I'm not sure how accurate the cc is - like I said yesterday the water turns a very light pink upon adding the CC reagent (0003 I think) - ( usually on my pool water it turns very dark pink because the CC is so high) but when I add the titrating reagent the light pink is totally resistant to turning clear. This morning it took 70 drops to get it clear - and once it sat for a minute, turned pink again, and continued to turn darker.

I have no idea what is going on. I decided to test my pool water this morning too - just to make sure I wasn't screwing up the procedure of testing and I got good numbers; FC = 3.5 ( last test was 4 2 days ago with no new bleach) and CC down to 4.5 ( last test was 20 2 days ago)
The water responded appropriately to the titrating agent.

I don't know what to do now. Add more percarbonate to the bucket? Add more bleach to my pool? Start draining???????? aciam

chem geek

06-23-2011, 02:43 PM

Mmmm... that's interesting. Maybe the very light pink that persists is some other interference either from some strange CC or from the hydrogen peroxide. Tell you what...why don't you add chlorine to the bucket until you measure a consistent FC level and then we'll see if the CC still has this weirdness. I don't think the CC is actually very high at all -- it's just got some strange test interference.

By the way, at least the CC seems to be dropping in the pool itself. That is consistent with another report where it took about 2 months for the CC to go away. So with the percarbonate approach we're really looking at seeing if it can accelerate the process. Let us know what happens in the bucket after you add the chlorine to it.

aciam

06-23-2011, 03:40 PM

Thank you chem geek - I knew it seemed weird. Well, my husband and I decided to drain the pool since it is almost july and we will be lucky to have 8 more weeks of swimming here in massachusetts. we are draining as we speak and have water being delivered tomorrow. I just don't want to wait another month to swim and essentially miss out on the summer. but if I have time, I will add bleach to my bucket just for kicks to see what might happen and report the results to you. I have 6 pounds of the percarbonate that I will have to find some other use for! Maybe I should send it to reesie! Hope she had a good day with her pool!

i will need instruction as to how to start up the new water with chlorine. Can someone give me the cliff note version? or is there a page on the forum that will guide me?

Thanks to all for the help. aciam