Product to lower CYA

[illinipdx]

I think I read on this forum about a product to lower the CYA. We have a vinyl liner pool and are doing the drain and replenish water routine, but we can't drain very far with the liner. I'd like to supplement this with a chemical to help if one is available. Does anyone know of such a product?

Thanks

[Simmons99]

I think a really bad case of algae might eat some - but I don't know of a chemical.

I heard that you can take a large sheet of plastic and place it on the top of the pool - drain from the bottom slowly and themn slowly add water to the top of the sheet of plastic. You can do a complete replacement without the risk of the liner being displaced.

[tenax]

how high is your cya that you have to drain that low???

[sailork]

A few months ago Waterbear posted something about using the same chemical that is used to test for CYA to cause the CYA to percipitate in the pool. Basically you add it, the pool turns milky and then you filter out the milkiness which includes the CYA.

I can't find the old posting, but I seem to remember that the stuff was so expensive that it probably wasn't worth it.

[aylad]

The chemical is melamine, which is the same chem used in the CYA test that clouds the water so the dot is obscured. Basically it's supposed to cause the CYA to precipitate out so that it can be vacuumed up, but I can't imagine putting that stuff in your pool on purpose. Much easier to drain/refill, and probably cheaper too.

Then again, you can also do the swamp thing....let your pool go green for a few weeks and it will degrade the CYA..........but I really don't recommend that one, either! :)

Janet

[waste]

Illin, welcome to the forum, you've picked the right place to find no BS answers to pool care (not to say that BS never shows up here, but it gets cleared out quite quickly). Unless you have your pool over a stream, you should be able to drain 2 1/2 - 3' at a time without fear. If you use the sheet method advocated here (get a really big plastic sheet - enough to cover the pool with a ~5' overlap all around- and put a pump in under it to remove the 'unwanted water' and turn on the garden hose on top of the plastic. The plastic keeps the fresh water from diluting the water you are pumping out, and refills the pool at the same time :) * Don't use this method if you have 'fill water problems' (metals or whacky chems in the tap water.
Good luck with the cya lowering, hope this helps. If you need more help, all you have to do is ask! -Waste

[illinipdx]

Thanks for all of the input. This is my parent's pool in Illinois, and I'm here for 3 weeks trying to get things fixed. I have a small Intex 15' pool in Oregon, and this site has made maintaing it so much easier. I'm hoping to get my parents pool in shape, and get them converted to BBB, etc.

I'm using the taylor k2006 test kit. The first time I tested CYA per the directions, the dot wasn't visible at a pretty low level, well below the 100 mark (so higher CYA level than 100). I then diluted 1/2 pool water and half tap water, and it's still below the 100 mark. All this says it must be >200.

We've got water rationing regulations right now, and the pool is large enough (L shaped 16'x40' in both directions) that a plastic sheet isn't possible for the drain/refill method you described. That's why I'm trying to find an alternative.

On a positive note, I did print out and have my Mom read some of the material here, and pool chemistry overview on one of the posts. She wasn't really buying my pleas to stop using stabalized chlorine until she read what I printed. Tonight, she was telling me how bad the stabilized stuff is! Yeah. Now, if we could get the CYA fixed...

Thanks again.