aciam - Nightmare conversion from baquacil to chlorine

[waterbear]

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]

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]

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]

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]

FYI. The procedure is in this PDF file (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.

[waterbear]

FYI. The procedure is in this PDF file (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]

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