Super high combined chlorine

[themaccs]

Help!! Started having problems the end of last season with chlorine disappearing - at that time I had a CYA over 100. I don't remember having problems with high CC levels - just chlorine disappearing like crazy. Fast Forward to trying to get things going this season. My CYA dropped to between 30 and 40 and I can't seem to get rid of my really high combined chlorine levels. Earlier this week I had pretty good readings at the pool store (didn't have refills on some of my home testing agents yet) - FC - 2.5, CC - 0, pH 7.4, TA - 180, CH - 210, CYA - 40. Pool is 19,500 gallons. I made the mistake of not testing for a couple of days and yesterday when I tested CC was out the roof again. I added about 10 gallons of bleach (6%) last night. This morning readings are as follows:
19,500 gal vinyl liner pool with cartridge filter
FC - 0.2
CC - 5.5
pH - 7.2
TA - 160
CH - 210
CYA - <30 (but looks like it is pretty close to 30, certainly above 20)

Water looks almost perfect - a little foam when I first open the electric cover in the morning that goes away as soon as the cover is open, but otherwise pretty much clear.

My plan for the day - add 17 gallons?? (do I really need this much? - I am really concerned about damaging liner) bleach this morning and brush, check again at noon and add chlorine as needed, check again this evening and add chlorine as needed - and keep doing that all weekend. I may use a little stabilized chlorine to get my CYA up just a bit. Am I on the right track? How do I handle my pH with my TA high?

Thanks for any help you can offer me!

[aylad]

First of all, welcome to the forum!! We're glad to have you here....

So, to help with your questions...
First of all, I would leave your TA alone. In a vinyl pool, 160 is okay. Depending on your fill water, it may lower some over the summer due to splashout and refilling, or if your pH gets too high and you have to lower it, you can deal with the TA at the same time. For now I would leave it alone, it's fine.

I'm a little confused about your high CC reading--are you sure you don't have the CC and FC backwards? A pool with 5.5 CC and only .2 FC ordinarily wouldn't be clear. What testing method are you using? Total Chlorine = Free chlorine + combined chlorine.
Either way...to reduce CC, you can do two things: 1) leave the pool uncovered during the day, and let the sun help remove the CC, and 2) shock the pool. With a CYA of 30, you need to get your chlorine up to 15 and hold it there until the CC is gone. In your pool, each 1 1/2 quart of 6% bleach will raise your FC by 1 ppm, to go from .2 FC to 15, you would want to add 5 gallons of bleach. Test for FC and add whatever amount of bleach you need to bump it back up to 15, and the more often you can do this the faster the CC will clear. Once the CC is less than 1 ppm (hopefully 0) you can let the Cl drift back down.

Do not add 17 gallons of bleach at a time--you will kill your liner!!

Janet

[chem geek]

It sounds to me like the pool was "let go" (i.e. not chlorinated) over the winter and that bacteria have converted some of the CYA into ammonia. That would lead to a huge chlorine demand upon opening and initially any chlorine added to the pool would form monochloramine which registers as Combined Chlorine (CC). I describe this technically in this post (http://www.troublefreepool.com/degradation-of-cyanuric-acid-cya-t8880.html) and describe my own experience with this in this thread (http://www.troublefreepool.com/it-can-happen-to-anyone-zero-chlorine-cya-ammonia-t10974.html).

The bad news is that if the bacteria truly converted around 60 ppm CYA into ammonia, it would take at least 150 ppm FC cumulatively added to get rid of. Hopefully, some of the ammonia outgassed so that the actual amount needed won't be that high, but it will take a lot regardless. So keep adding chlorine with the pump running adding it over a return flow in the deep end and measure the chlorine level after 30 minutes. If the FC is still low, add more chlorine. The CC may continue to climb, but keep adding chlorine until the FC starts to rise. At some point you'll reach breakpoint and the CC will start to drop.

Do not add any stabilized chlorine at this point. A higher CYA level will only make the process of getting rid of CC take longer. Do not worry about the pH and TA at this point either. Having the lower pH to start with is fine since shock levels will tend to raise the pH anyway (at least temporarily when the FC gets high)

To prevent this problem in the future, maintain chlorine in the pool over the winter. If you live in an area where the pool freezes over, then shock the pool with chlorine when it gets below 50ºF and then open the pool up again before the temps get above 50ºF. Chlorine usage is very low at colder water temps.

Richard

[themaccs]

Thanks for your reply - No, I do not have the numbers backwards- My guess is that I have the situation Chem Geek describes in his response and the only thing I know to do is to keep adding chlorine. So I guess I'll keep adding and checking, adding and checking and pray my liner survives.

[themaccs]

Thanks chem geek - I had pretty much come to the conclusion I must be experiencing what you are describing. With fear and trepidation I went ahead and added the bleach like I described - an hour and a half later I still had basically no FC but the CC was down to about 2.5. So I added some more and will check again in 30 minutes, i sure hope i am not destroying my liner. We did have it closed professionally? at the close of last season - I wonder if they forgot a step?

[themaccs]

Well, I don't think I would have believed this if I hadn't experienced it. I have been adding chlorine following Chem Geeks experience ( Thanks - wouldn't have had the courage to do it otherwise!). Gave it a really large dose yesterday morning and then retested and added bleach every 1-2 hours all day yesterday about 1.5 - 3 gallons at a time. Now, some nearly 35 gallons of bleach later, I am still not there yet. I went ahead and added some stabilized chlorine (I was out of bleach) this morning because my FC was down to 0.8 and my CC was still 1.2 and I was afraid to go off to church for a couple of hours and lose the last of my FC. That did get my FC up to about 15, but it is already back down to 2.5 with CC now at 0.8. Off to get more bleach and I will continue today as yesterday. I'm sure glad its a long weekend and I have time to deal with this! I don't know what the nasty thing is that's in my water - but I sure hope I can finish killing it today!! The amazing thing is the water is crystal clear!

[chem geek]

If you want to know how much more chlorine it will take you can do a bucket test where 1/4 teaspoon of 6% bleach in 2 gallons of pool water is 10 ppm FC. That will tell you how much cumulative FC you have left to go. If one does this initially, then one can decide whether it's better to do a partial drain/refill if water is less expensive than the amount of chlorine required. One can also get an inexpensive ammonia test kit from a pet/fish/aquarium store to get some idea of the ammonia in the water (though that's only part of what needs to get oxidized).

As for adding CYA, just note that it will slow down the rate of the oxidation process. The plus side is that it will retain the FC longer during the day protecting it from breakdown from sunlight, but right now your FC seems to be mostly getting consumed oxidizing the ammonia in the water and that's much faster with no CYA in the water. Normally I recommend not adding CYA until your FC is holding longer. If the FC only drops by 50% in an hour, then that's the time to add CYA since that drop can be from sunlight. If it drops a lot more than that, then it may not be worth having the CYA. If you do add CYA, don't add very much -- even 10 ppm or 20 ppm is plenty at this point, but will slow down the oxidation process by over 10x. Finally, you'll know that sunlight and no CYA are not an issue yet if you add chlorine at night with the sun off the pool and still find the FC getting used up rapidly.

As far as your liner is concerned, just keep the pump running while doing this process and pour slowly over a return flow to ensure thorough mixing and lightly brush the side and bottom of the pool where you add chemicals. Your liner will be fine.

(On a side note, in a conversation with Ben I found out that he first discovered this effect long before I did and wrote about this here (http://www.poolforum.com/pf2/showthread.php?p=465) and here (http://www.poolforum.com/pf2/showthread.php?p=3428) and in earlier posts. I just independently worked out some of the chemistry involved based on known CYA degradation pathways to come up with some low and high range quantities.)

[themaccs]

Thanks for your help. To say i am frustrated is indeed an understatement. I have already used over 50 gallons of bleach. FC still dropping like crazy overnight and CC which was staying at about .8 during the day yesterday has been staying at about 2.0 since the sun went down yesterday. Decided to drain some water off today, but don't know how much I will be able to accomplish because the pump we use limits us to being able to only drain about 8 inches off, not to mention that i am scared to death of really messing things up with the liner if we drain too much off. So, with the bucket test thing I guess I am trying to create a mini version of my pool? I'm a little concerned about the time that will take in addition to the fact that i don't have an unlimited supply of testing reagents. At this point I guess I am inclined to just put the 8 inches of fresh water back in the pool and continue where I left off with the addition of chlorine. Am I wasting chlorine adding during the day? I thought I understood that it would be best to keep my FC at shock level for as long as it takes to get rid of the CC AND keep my FC from dropping overnight, so my goal at this point has been to keep my FC at between 15 and 20, checking every hour or so and adding whatever it needs to get back to that level. I can do that today - but i have to go back to work tomorrow! Most recent results (before we started draining the 8 inches off:
FC - 16
CC - 2.0
pH - 7.2
TA - 160 ( i have been checking this just once a day)
haven't rechecked CH - seems irrelevant at this point
CYA - 35 - 40 ( i did add some stabilized chlorine yesterday morning since when i woke up FC was down to about 2 and we were out of bleach - didn't want to lose FC while we were at church!)

Again, thanks for the input. Hind site is always 20/20, but in retrospect i should have been more concerned and diligent about figuring out what was going on when the pool started eating chlorine at the end of last season. Didn't have the CC issue then, though, just a bear of a time keeping FC in the pool at all. And a CYA of at least 100 makes me think that some bacteria was introduced at some point so that even though the pool was closed properly last season, the bacteria or whatever had several months of enjoying their CYA meal and "pooping" out ammonia. This is costing me not only with the money I am spending on chlorine and fresh water, but in time and frustration as well. Live and learn!

[themaccs]

P.S. : I thought I might back up a little bit and introduce myself and explain how i got here. I have been lurking in the backround, following advice here (sort of) for about 5 years. We were living in GA then and I found testing the pool myself and managing with a modified BBB (we used a chlorinator and occasionally some stabilized shock) pretty easy- and it beat trying to get a sample to the pool store for testing. It worked pretty well, but then our pool liner ended up getting bleached out and we wondered if it was from using the bleach. That didn't really make sense to me, but at my husband's gentle suggestion, we went back to pool store management of our pool. Then we were transferred here to Kansas in July of 2008 and bought a house with another pool. We continued managing the pool store way, and then for some reason last year I got concerned about that my CYA level might be way high (pool store seemed to ignore CYA) and did a test myself - the results were crazy - I think up around 170! We drained some water out of the pool a couple of times, and I got it down to around 100. I decided to leave it there for the season (now I know a big mistake) and manage with the BBB method and some algicide. This season we took the first couple of samples to the pool store, and while I think the testing methods were accurate and their advice was ok - using lithium chloride to shock at the level and frequency i was needing got really expensive really fast!!! So I started in again testing myself and using bleach. I got frustrated pretty quick because I couldn't keep FC in the pool. My husband's advice was to go back to the pool store and do whatever they suggested to get things fixed. I didn't really want to do that - the expense would have been ridiculous. So, I started searching this site to find an explanation and a plan for fixing the problem. I think i convinced my husband that the advice on here makes some sense and won his support in the process. So here we are, frustrated that this is taking so long and wondering if we will ever get it fixed. But I am fairly convinced that I would be messing with it all summer and swimming in a questionably safe pool if we continued with the pool store advice - not to mention the cost! This way, i am hopeful that once we get this issue fixed correctly, I might be able to enjoy the rest of the summer in an easy to maintain pool. So, thanks to all you experts for being here!

[aylad]

I'm glad you found us and posted here. The ways that we describe here DO work! Sometimes it takes a little longer to get where you want to be, but you have to remember that it took about 2 years for your CYA to build up to the point where it broke down into this much ammonia demand, so an overnight fix is just not possible. And at least bleach is much cheaper than lithium!!

It is easy to get frustrated with it, and to doubt yourself, and to just "give it back" to the pool store--but believe me, you'll have this problem fixed soon and enjoy a whole summer in a clean, clear pool, where if you go with the pool store, this is a battle you're gonna fight all summer long. Patience is hard to come by sometimes, but it's a necessary evil!!

We're glad you're here....

Janet

[chem geek]

So, with the bucket test thing I guess I am trying to create a mini version of my pool?
Yes, that is correct. It's just easier and less expensive than dumping a bunch of chlorine in the pool. If the amount left is huge, then water replacement could be cheaper/easier.

Your high chlorine demand at the end of last season when the CYA was still high was likely due to nascent algae growth since you'd have to maintain a much higher FC level to prevent that and have to shock at even higher levels. The water probably had lots of nutrients for algae as well. When you closed for the winter, the FC went to zero and bacteria had a great time dining on the nutrients in the pool including the CYA that was there. If the CYA dropped from 100 to 30 ppm, then that 70 ppm could get converted into around 20-25 ppm ammonia that would require roughly 200 ppm FC to get rid of. That's worst-case, but is an extraordinary amount of chlorine required to be cumulatively added.

[themaccs]

It is easy to get frustrated with it, and to doubt yourself, and to just "give it back" to the pool store--but believe me, you'll have this problem fixed soon and enjoy a whole summer in a clean, clear pool, where if you go with the pool store, this is a battle you're gonna fight all summer long. Patience is hard to come by sometimes, but it's a necessary evil!!

We're glad you're here....

Janet

Thanks for the encouragement. I guess I'll keep chugging away with the bleach. We're kind of at a stand still today - the good news is I'm able to keep the FC up with a dose every few hours and the CC has been between 0.5 and 1.0 all afternoon (1 drop almost clears the pink, 2 wipes the pink out easily - I would try a 25ml sample but I don't want to use that much reagent). I have managed to keep the FC between 10 and 18 all day (CYA is 40). The bad news: every time I test the results are about the same: losing about 4ppm FC every 2-3 hours, CC staying at between 0.5 and 1.0 ). I feel like this is the same place I was yesterday when the sun was shining, then the CC jumped up to 2.0 when the sun went down. I've used close to 75 gallons of bleach so far. I hope I am getting close! And I know it will be worth it when I have the rest of the summer with a clean clear pool without daily trips to buy more bleach! Thanks again for the encouragement!

[themaccs]

If the CYA dropped from 100 to 30 ppm, then that 70 ppm could get converted into around 20-25 ppm ammonia that would require roughly 200 ppm FC to get rid of. That's worst-case, but is an extraordinary amount of chlorine required to be cumulatively added.

So if my math is right (and I'm not at all sure it is), 200ppm FC calculates out to roughly 70 gallons of bleach in my size pool (19,400 gal). I have used about 75 already, so hopefully I will be done soon. Unless of course the scenario is really much worse and my CYA was much higher at the end of last season. I know when I first discovered how high it was it was over 150, but we did drain some and dilute and I'm pretty sure I got it down close to 100 - but I know I was still having to dilute my sample to be able to test it, so it may have been higher. Ugh! After putting all this into it, just not too sure I'm ready to drain and dilute. We would be hiring someone to do that since i am not willing to risk messing my liner up doing it ourselves, and that would surely be more costly! Thank goodness for Sam's and cartons of big jugs of bleach!!

[chem geek]

You are at the point now where you need to measure the FC loss overnight when the sun is not on the pool. I suspect that this may not be a very big loss in which case sufficient CYA in the pool should protect the FC from dropping too much during the day. I think you are pretty close to being done -- at least I hope so.

[themaccs]

Well, I think I am seeing the light at the end of the tunnel!!! An hour ago I added 2 quarts and 2 cups of bleach to get FC to 16 because I had a FC of 12.5 and a CC of between .5 and 1.0. It's still light but no sunlight hitting the pool. Took a walk and tested again: FC now 15.5 and CC 0.5 - 1st time I've cleared the CC with 1 drop since I started this thing!! Plan for tonight is to continue to test hourly and add bleach as needed until about 11 when I go to bed - then see how the FC holds overnight, testing 1st thing in the morning. Thanks for the help and encouragement!

[chem geek]

It does sound like you are near the end. Just keep in mind that the easy stuff that oxidizes readily has been taken care of, but there may still be some remnants of partially oxidized CYA that will be somewhat slower to oxidize and get rid of. You are definitely close and should see your total chlorine demand go way down at this point.

So if your CYA is low, raise it so that you don't lose too much from sunlight during the day. You should have it at least at 30 ppm, but 50 ppm is fine as well and is more typical for pools in the sun (pools in a LOT of sun, such as Arizona, sometimes operate at 80 ppm to minimize chlorine loss, but you have to be very diligent about maintaining chlorine in such pools since it takes more chlorine to shock them to get rid of algae).

It's interesting (and somewhat comforting to my nerdy personality) that the total amount of chlorine needed was in the ballpark of that predicted based on the CYA loss, which was a rough guestimate to begin with.

Richard

[themaccs]

So if your CYA is low, raise it so that you don't lose too much from sunlight during the day. You should have it at least at 30 ppm, but 50 ppm is fine as well and is more typical for pools in the sun (pools in a LOT of sun, such as Arizona, sometimes operate at 80 ppm to minimize chlorine loss, but you have to be very diligent about maintaining chlorine in such pools since it takes more chlorine to shock them to get rid of algae).

It's interesting (and somewhat comforting to my nerdy personality) that the total amount of chlorine needed was in the ballpark of that predicted based on the CYA loss, which was a rough guestimate to begin with.

Richard

My CYA was at 40 when I checked it earlier today - I had to use a little stabilized chlorine yesterday morning when i ran out of bleach. So it looks like I am good there. We do get a lot of sunlight on the pool, so I will have to see how that goes once I see whether or not I am loosing any at night. I think I will be able to get home mid-day tomorrow to check on it.

I am still loosing a bit of FC, just added 1 quart + 3 1/2 cups because it had fallen to 14.5 and the CC was back up a little over 0.5. But it is nice to be adding bleach using my pint measuring cup rather than by the jug full!

I can appreciate the comfort you receive from knowing your guestimate was in the ballpark - my personality works the same way.

The cloudiness in front of the light in my pool is nearly gone as well! YAY!!

Thanks again for your support and encouragement - not to mention your willingness to share your knowledge and experience!

[themaccs]

Well, i am still fighting, but perhaps not quite so hard. FC dropped from 15 last night to 10.5 this morning. CC was at 1.0 last night, up to about 1.5 this morning. I added 1 1/2 of the large (182 oz) jugs of bleach (so about 275 oz). Rest of my numbers look like this: pH - 7.2, TA - 150, CH - 200, CYA - about 45. I plan to come home mid-day to check on it.

[aylad]

Sounds like you're almost there. You'll know for sure when the Cl stops dropping overnight, when tested in the evening and again in the morning before the sun hits the pool. Just a note--I'm one of those that keeps my CYA intentionally 80-90 because I live in Louisiana with my pool in full sun all day. If I keep my CYA below 60, I lose almost twice as much chlorine during the day as I do with my CYA at 80. It's an unusual case, I know, but I'm just saying it happens.........

Janet

[themaccs]

Mid-day not too bad - FC - 11, CC - just over 0.5 (1 drop almost cleared it). So another jug and 1/2 of bleach (about 270 oz). Seems like i haven't really lost much more FC between 6:30 am and now (1:10 pm) as I did between 11:00 pm and 6:30 am this morning - almost the same number of hours, but a LOT of HOT Sunshine today.

[themaccs]

Back to being a little frustrated. I seem to be stuck. Still losing between 5-6ppm FC at night. Stuck at about 1ppm CC. pH - 7.2, TA - 150, CYA - 45-50 (i have a little trouble deciding exactly when I can't see that dot!). I have some time at home again today - is it best to try to keep my FC up at shock level as consistently as I can by doing the every hour check thing again today? Or is the cumulative amount of bleach going to be the same no matter what? Yesterday - partly because of working, partly because of wanting to be able to swim in the evening, we let the FC drift down to 8-10 a couple of times, then dosed it back up last night.

And how soon after I dose the pool can I check to get an accurate reading of my shock level? - I have been calculating what I need using the pool calculator, then testing an hour or so later. I am assuming that I reach shock level when I put the calculated amount of bleach in, but since I am still losing some and not checking till an hour or so later, I have never actually had a test read out at shock level. I am considering my shock level at this point to be close to 20 since my CYA is close to 50. The highest test reading I have had as been 16.

Am I missing something?

[Watermom]

I think you just have to keep at it. As soon as chlorine goes in, it starts to get to work. Yes, to your question about trying to keep at shock level as consistently as you can. The more often you test and add bleach back up to shock level, the faster this is going to get finished. You can't test and dose TOO often. I have no doubt how frustrated you are, but keep hammering it with bleach!

[themaccs]

I think you just have to keep at it. As soon as chlorine goes in, it starts to get to work. Yes, to your question about trying to keep at shock level as consistently as you can. The more often you test and add bleach back up to shock level, the faster this is going to get finished. You can't test and dose TOO often. I have no doubt how frustrated you are, but keep hammering it with bleach!


Thanks for your quick reply! Off to buy some more bleach :)

[AndyJ]

This must be exactly what I experienced this spring. I had heard of CYA-eating bacteria, but didn't realize this would result in more that simply needing to add stabilizer. I had good to high CYA levels last fall (guessing 50-100) and none this spring. Took 102 gallons of bleach before it would hold FC levels.

I'm now looking for ways to prevent this from happening next winter. I'm guessing some combination of chemical levels during winterizing and earlier spring startup. FC was 0 last fall when closed up, and this spring, it had been ice-free for about a month or so before we opened it.

Pool is a 24k IG with SWG. I live in Minnesota, so it freezes hard from about December through March.

[chem geek]

You can prevent this problem by maintaining an FC level in the pool at all times. Obviously you can't easily add chlorine, let alone mix it well, in a pool that is frozen over, so the next best thing is to wait to close the pool until the water temp gets as cold as possible -- at least below 50ºF. At that point, chlorine will last for quite some time so if you close with a shock level of chlorine or even a higher than normal level, it should last through the season. This is especially the case if you use a pool cover that is opaque to sunlight. If your pool is exposed to the sun, then the chlorine will drop even when the water temperature is cooler.

I know that in my own pool the chlorine loss drops to less than 1 ppm FC per week when the water gets to around 50ºF and I suspect that when near freezing the chlorine loss rate is less than half that. However, I have a mostly opaque safety cover.

You should then open the pool before the water warms up, so definitely before it gets above 50ºF.

There are other ways to avoid the problem that involve the use of supplemental products (PolyQuat 60, for example) at extra cost, but the above method using chlorine alone is simple and inexpensive.

[AndyJ]

Thanks, chem_geek. I read the fall closing sticky thread and it said to maintain FC all winter. The author mentioned checking the chlorine periodically throughout the winter and adding it as necessary, but as you mentioned, I couldn't see how that is possible if my pool is frozen solid. I see now that I can just raise it to a high level to last the winter. I do have an opaque auto cover, so that will help prevent FC loss.

However, I also saw mentioned that FC should not be too high, or it might damage my cover, since it will not vent excess chlorine fumes well. I'm guessing a level in the 15 ppm range might be a good medium upon shutting the pump down, say when the water temp is about 40-45.

I did see PolyQuat mentioned as well, so I may give that a try. With your advice, I'm hopeful my situation will be much better next spring. Thanks again.

[chem geek]

Because you'll have CYA in the water, the active chlorine level is actually quite low. Even if your FC were around 40% of your CYA level, the active chlorine (hypochlorous acid) level is the same as found in a pool with 0.6 ppm FC and no CYA. So this is not extraordinarily high. Also, at the much colder temperatures all chemical reactions slow way down.

Nevertheless, to minimize any potential issue, close as late as possible and open as early as possible which is what it sounds like you will be doing. 15 ppm FC with, say, 50 ppm CYA will be like 0.4 ppm FC with no CYA. If you had your CYA higher at 80 ppm that is more typical for SWG pools, then the 15 ppm FC with be like 0.2 ppm FC with no CYA so quite reasonable.

[AndyJ]

So, do you think FC should be higher than 15 upon closing? I plan to have my CYA in the SWG mfr recommended range of 50-75 ppm. Looking at the best guess CYA chart on this forum, that would correspond to a shock level of about 20 ppm FC.

EDIT: not sure it matters, but I also have a Nature2 cartridge.

[chem geek]

I think the 15 ppm FC will work fine even with 50-70 ppm CYA. You can measure the FC upon opening next year to see how well it held up over the winter. If it's high, then you won't need to close as high.

You have a Nature2 cartridge for a pool? Ditch it (leave the cartridge holder empty). It's obviously not providing any benefit preventing bacterial growth and the metal ions it releases can stain pool surfaces if they get high enough to do any good and if the pH gets too high for whatever reason (which can happen over the winter).

If you wanted to have any form of supplemental algaecide, then use 50 ppm Borates in the pool. I don't know if that's enough to prevent bacterial growth -- probably not -- but it will slow down algae growth and at colder temps might be enough to slow down bacteria if the FC went to zero for whatever reason.

In my own pool I had some metal staining over this last winter due to iron that is still getting into the water from some stainless? steel mounts that got rusted when Trichlor pucks in a floating feeder parked nearby 7 years ago. The acidity of the Trichlor rusted the mounts (they are for holding stainless steel bars that are just under the waterline). I cleared this up with an ascorbic acid treatment and metal sequestrant (lowering the pH back down from when it rose over the winter also helped).

[AnnaK]

I would like to jump in with my personal experience (and method) of closing late and opening early.

We drain some of the water from our AGP so we can disconnect the plumbing because all freezes solid by January. I close with FC at 18 ppm and CYA at 50, usually at the end of October. By then, the water temp is at or below 50 F.

As soon as most of the ice has thawed at the end of April I take a sample and let it come to room temp before testing. My water has always been clear in the spring. FC will be around 3 ppm and CYA will be below 30. We don't reconnect the plumbing until we're past the last hard frost times at night but because it can get prety warm during the days the water temp quickly moves above 50 F.

So, I add chlorine and mix it in manually by using the brush or the leaf net on the long pole. This is very effective in distributing chlorine when you don't yet have the pump running. Once the pump is back on line I use trichlor in the feeder for a few weeks until I have the CYA where I want it and then go back to liquid chlorine.

From my observation, the trick is to get chlorine into the water while it's still very cold to inhibit the growth of CYA-destroying bacteria.

[AndyJ]

Thanks AnnaK, that post is very helpful. I am possibly going to attempt winterizing my pool this fall for myself for the first time on our 4-year-old pool.

[Watermom]

Oh, sure! You can do it. We'll still be here in the fall if you need some help and encouragement then, too! Glad to have you as a part of our forum!

[themaccs]

I am ready to quit. Seem to be going backward. Still loosing about 6-7 ppm FC over night and 1-2/hour during the day. Now at close to 100 gallons bleach. This morning my CC was back up to 2. I need to have a life besides my pool! I have not allowed the FC to get below 10, keeping it most of the time between 12 - 18. Everytime I think we are making progress, i get another high CC reading! One possibility - the birds like our backyard and we have noticed a fair amount of bird droppings on the pool deck. We do cover the pool with an opaque automatic cover at night, but if droppings are getting in the pool during the day, could that be adding to my problem? I thought the sun was supposed to help the CC go dissipate quicker, so I have been uncovering it during the day - should I try leaving it covered?

[aylad]

If you get an occasional bird dropping in the water, it's not going to cause the kind of CC's that you are experiencing--I have swallows that drink out of my pool and regurg stuff on a regular basis, and my CC never goes above 0.5.

Other than keeping the pool at shock level to burn off the CC, I don't really know what to tell you to do other than try to identify where they're coming from. Is it possible that the pool surface is degrading and causing it? Are you positive that your testing methods are correct and that you're using fresh reagents? I know those questions are redundant, but I'm just muddling over your situation trying to figure out what other approach we can take. I understand your frustration and would feel the same way--but don't give up on it yet...

Janet

[Watermom]

Your thread in particular was one we discussed with Ben. He says if you are losing chlorine over night, then you just have to keep hammering it with bleach. I know it seems like it will never end, but one morning you're gonna get up and find that you haven't lost chlorine overnight! There is nothing else to do but keep at it. Every day consistently and you will win. (Please know that we understand your frustration. We are frustrated, too, because there is nothing new to tell you that we haven't already said. Now it is just time to stay the course and don't give up. I'm sure that doesn't help much, but there is no other easy cure. Wish there was ... :rolleyes:

[AnnaK]

The major issue is to keep the chlorine up very high all the time. You've mentioned letting it drop down to 10 ppm occasionally. That doesn't help the situation. You've also allowed the CYA to creep up from 30 to 50 by using stabilized chlorine products, which means you'll need more chlorine. This is a project and a process. It's not the time to run short of or out of chlorine.

One approach other than chlorine to kill the bacteria might be UV irradiation with a UV bulb. You could place it in the skimmer so it hits all the water being sucked through the intake. Where to get such a bulb and how much they cost I don't know. UV irradiation is used in some homes to sanitize well water, it's not just a scifi concept.

100 gallons of bleach put into a pool without any obvious progress would frustrate the heck out of anybody and I do sympathize with you. We all do. At this point you need to exercise some extreme discipline. No swimming, no slacking off, no substitutions. High concentrations of bleach 24/7. You almost had it beat once. You can get there again.

[themaccs]

Thanks for all the encouragement. Not sure how exactly to do what you are saying i need to do. I don't think my employer would understand if I had to take a few days off so i could keep chlorine in my pool. Today is a good example, FC was 18 when I left the house this morning, I had a long busy day at work, FC is now 7. What to do?

[Watermom]

Obviously, you can't babysit your pool 24/7. But, just test and hit it with bleach as often as you can. Before work, as soon as you come in from work, a couple hours after that, before bed. Whenever you can. The more often the better. Good luck and please keep us informed how it is going.

[themaccs]

I Is it possible that the pool surface is degrading and causing it? Are you positive that your testing methods are correct and that you're using fresh reagents?

Janet

Just received fresh reagents in the mail yesterday, and the ones I have run all the way through trying to keep up with this were new 2 weeks ago. Pretty sure my method is correct. How would I know if my pool surface (vinyl liner) is degrading? There are no areas of discoloration or other indication of damage. Guess I'll try to keep up the bleach. How safe is it to take it up close to 30 in the morning so it doesn't get as low during the day when I can't be here?

[Watermom]

Geez. I don't know. As fast as your cl level is dropping, it probably wouldn't stay at 30 for long but I can't tell you that it won't fade you liner. What is the highest you have shocked it to thus far?

[themaccs]

Geez. I don't know. As fast as your cl level is dropping, it probably wouldn't stay at 30 for long but I can't tell you that it won't fade you liner. What is the highest you have shocked it to thus far?

About 22, didn't stay there long though.

[aylad]

If there's no fading of your liner, and no strange "feel" to it, then liner degrading isn't the problem. At the time I wrote the post for some reason I was thinking you had a gunite pool....just kind of "thinking out loud".

With a CYA of 50, I'd hold off on shocking to 30--try going to 20 instead. There was one time in the past that I actually shocked mine to almost 40 and held it there for about 3 weeks with no apparent liner damage, but that was a very extreme case and I wouldn't recommend it, just to be on the safe side.

Janet

[themaccs]

So - is there another test I should be getting done on my water, or should I be throwing in the towel and doing a drain and refill? I have really thought for the last several days that we were almost there: I have been dosing the FC up to 20 ppm or slightly above before leaving for work in the morning, checking it as soon as I get home and trying to keep it above 16 all evening, then up closer to 20 before bedtime. FC was down to 10.5 when I got home after an extra long work day yesterday, and down to 11 when I got home today. Basically, FC has been dropping 1-2ppm/hour during the day and 4.5-5ppm overnight. CC was holding pretty steady at around 0.5 or slightly above. Then my readings when I got home from work today are as follows:
FC - 11 (down from 21 in about 6 1/2 hours - a short day at work)
CC - 1.5
pH - 7.6

TA is holding at about 160
CYA is staying at about 45.

Now have added close to 120 total gallons of bleach.

I really thought we were getting somewhere this morning when the CC barely showed up, but then that was followed by the worst readings I have had in several days this evening. We did have a fair amount of rain overnight last night, but not since this morning's testing and dosing.

So - is there another test to figure out what I am dealing with, or is it time to just drain and refill, or should I keep hammering the bleach?

Thanks for any insight you can give me!

[themaccs]

There was one time in the past that I actually shocked mine to almost 40 and held it there for about 3 weeks with no apparent liner damage, but that was a very extreme case and I wouldn't recommend it, just to be on the safe side.

Janet

Can i ask what the extreme case was that you needed to keep you FC at almost 40 for 3 weeks? I'm needing some hope that this will eventually work - I am at almost 2 weeks on a job i thought would take 2-3 days!

[Watermom]

I'll let Janet answer about her need for high chlorine for 3 weeks.

I just wanted to tell you that it will eventually work. I have no doubt that you are totally frustrated and I don't blame you for feeling like throwing in the towel. But, there is no other alternative. You just have to keep hitting it really hard with bleach. I know it seems it will never end but it will. We have had several people in this same situation this year and some of them have made it through to the other side. You will, too. So sorry this has been so hard but don't give up.

[aylad]

Can i ask what the extreme case was that you needed to keep you FC at almost 40 for 3 weeks?

Yeah, if you really want to:eek:....The adult son of our next door neighbor committed suicide by drowning himself in my pool about 6 years ago, fortunately it was in October and at the end of the swimming season. In all honesty, shocking it at a much lower chlorine level for a few days would have been sufficient to make sure the water was clean, but it took about 3 weeks at extraordinarily high shock levels (and several water changes after that) to kill the "ick factor".

At the beginning of the next swim season I (overdoing it, as usual) called the head of the Infectious Diseases departments for our local 3 major hospitals and described the incident and my solution, just to make sure in my mind that the water was safe to swim in, and they all three actually laughed at me, said they'd drink the water with no problem and that my pool was probably the cleanest place in the state. Shocked it again after that, and THEN we went swimming! ;)

I know this is no help to you, and like Watermom, I understand your frustration, but unless there is something introducing large amounts of "stuff" for the chlorine to kill every night, the only thing you can do it keep it shocked and it will eventually burn off. Have you tested it for ammonia lately?



Janet

[sonocop]

Just wanted to say good luck to you and I hope you get your problem solved soon!

[Watermom]

sonocop, nice to see you back on the forum!

[themaccs]

I am so sorry you had to go through that horrible event. And I guess you are right - no real help for my situation. But thanks for the encouragement. And again, sorry you went through that.

"but unless there is something introducing large amounts of "stuff" for the chlorine to kill every night, the only thing you can do it keep it shocked and it will eventually burn off"

Is there something that might be able to introduce large amounts of "stuff"?

No, I never really have tested for ammonia - kind of just assumed that is what I was dealing with and that I had to do the same thing whether or not I knew the ammonia level. I am kind of wishing I had at this point. Would a really high ammonia level have smelled like ammonia? I have smelled the "chlorine" smell, but not anything I would say smells like ammonia.

[aylad]

You wouldn't necessarily smell ammonia--but there are test kits that will check for it, and they're pretty cheap--look in the aquarium section at WalMart or any pet store. Since you're been fighting this long and it still hasn't cleared, I would check to make sure that's what you're actually fighting. I guess I have been assuming all along that we knew for sure that there was ammonia in the water. It's the only reasonable explanation that I can come up with right now, but maybe we need to verify it.....

Janet