Super high combined chlorine

[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

[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]

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.