thx.
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
thx.
Yes, that's correct. In my situation, given the eventual chlorine demand and the amount of CYA loss I should have seen (if ammonia were present) very high CC levels over 30 ppm before it would have started to drop again, but in fact I only saw it rise to no more than 1.6 ppm CC. So the bulk of what was in the water was something other than ammonia, but that the chlorine reacts with albeit more slowly. I guessed that it was the intermediate breakdown products of CYA -- basically the bacteria weren't finished eating it when I got to them. We've seen other reports where the CC is high after adding chlorine and gets reduced rather easily and quickly, albeit needing lots of chlorine. For CYA degradation, it basically goes through the following steps so depending on where it stops you can end up with a mixture of different chemicals that will behave in different ways and you can get a mixture of any of the following:
CYA ---> Biuret ---> Allophanate ---> Ammonia ---> Nitrite ---> Nitrate
.................................................. ......... | .............. | .............. |
.................................................. ......... | ....... Nitric Oxide ... Nitrite
.................................................. ......... | .............. | .............. |
.................................................. ......... | ..... Nitrous Oxide ...... |
.................................................. ......... | .............. | .............. |
.................................................. ......... `------------`-------------`---> Nitrogen Gas
The following table shows the speed of chlorine demand for each chemical and whether it forms significant CC:
Chemical . Chlorine Demand . Forms CC
CYA .............. Very Slow .............. No
Biuret ............... Slow ................. No
Allophanate ....... Slow ................. No
Ammonia ....... Very Fast .............. Yes
Nitrite ............... Fast ................. No
Nitrate .............. None ................ No
Nitric Oxide ....... Fast? ................ Yes?
Nitrous Oxide ..... None? .............. No?
Nitrogen Gas ..... None ................ No
Last edited by chem geek; 05-17-2014 at 05:37 PM.
15.5'x32' rectangle 16K gal IG concrete pool; 12.5% chlorinating liquid by hand; Jandy CL340 cartridge filter; Pentair Intelliflo VF pump; 8hrs; Taylor K-2006 and TFTestkits TF-100; utility water; summer: automatic; winter: automatic; ; PF:7.5
Great stuff.
So I'd say in my case ammonia wasn't the biggest CL consumer since CC never got above .5ppm. Btw, I estimate I lost about 40ppm stabilizer over the winter (still had about 30ppm when I stated the pool up last weekend).
Too bad there's not a way to seal off the pool in the winter. While my solid cover does keep dirt and debris out, the worms and bugs love to get under there. Scooping out bunches of dead worms in the spring is so gross...lol. I'm sure all those critters introduce all kinds of bacteria to the water.
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
Tonight's test showed I lost 6ppm FC during the day (SWCG is off). It was partly cloudy today. I'll let the pump run overnight with the filter on to see how much I lose overnight.
If there is a loss, I think we can safely say something in the filter is consuming CL since last night with the pump off there was no loss. If the loss isn't that much I think I'll just let CL do it's job over time rather than tearing down the filter (or maybe shock it one more time). Tomorrow morning's test should tell us more.
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
This morning's CL test showed I only lost .5ppm FC (CC is still 0) overnight with the filter running. So I'm guessing that whatever was consuming CL overnight was knocked out by that last shock.
The good news is I can stop shocking and don't have to tear down the filter. The bad news is we don't know if the overnight loss was caused by gunk in the filter, in the pool, or both.
So once FC levels drop to normal, 5-6ppm, I can work on getting the SWCG set properly and get to a normal maintenance routine (which usually doesn't involve much with our pool). FC was 12.5ppm this morning so I expect by this evening it will be close to the normal maintenance level.
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
This post made me think of something. When closing for the winter I drain and take the DE filter completely apart and thoroughly clean the grids, tank, etc., so I don't get any bacteria/gunk buildup over the winter.
I've always done this because I was told if you let the DE sit over the winter and dry out, it can get like concrete and be very difficult to clean out. It didn't occur to me that another issue would be increased CL demand from all the bacteria/gunk buildup that would occur.
Thanks for bring that up.
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
Just a final (hopefully) recap;
Lost about 40ppm CYA over the winter.
Went through 25 gallons of 8.25% bleach before it would hold FC level overnight.
Now where's the heat!
22'x40' Grecian Lazy L 20K gal IG vinyl pool; Aqua Rite SWCG T15 cell; Hayward Pro Grid 6020 DE filter; Hayward Superpump 1hp pump; 12 hrs; Taylor K-2006; city; PF:6
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