cya help

[rhosk]

What does "very high" mean? If it was 200 ppm, then it looks like the partial drain worked.

And I would guess that "half" the pool/water would be hard to determine, at least for me. You will just have to keep trying to dilute - don't give up.

Edit: a lot of "same time posting" going on here. Popular place and plenty of help (very rare these days). Great forum!

[brent.roberts]

I had the same problem a couple years ago. I did 2 drainings of about 1/2 the water.

If your pool is vinyl lined, be careful. If you have high ground water levels it could get interesting and other stretching could occur.

If you already did a 50% drain and had no problems, do it again. If you are seeing some new wrinkles then try this.

Get a huge plastic tarp or plastic sheet that will cover the pool and give you several feet extra in each dimension. put your fill hose on top of the plastic and start filling, and then start pumping out water from under the plastic in intervals to keep up with the fill. The level in the pool will not change.

When you are satisfied with the amount, pull the plastic sheet out. Done deal.

I would be shooting for a CYA level of about 40 or lower. It's easy to get it back up if you want to. As you have discovered its a pain to get it down.

[njpool]

I was wondering if there were any other methods of reducing CYA besides drain-fill. Previous use of tri-chlor pucks have created a high concentration. I've now switched to using bleach.

I have done some net searches & saw a patent for using melamine, but wondered what else could be done. How long does it take for CYA to degrade or reduce naturally?

[waterbear]

I was wondering if there were any other methods of reducing CYA besides drain-fill. Previous use of tri-chlor pucks have created a high concentration. I've now switched to using bleach.

I have done some net searches & saw a patent for using melamine, but wondered what else could be done. How long does it take for CYA to degrade or reduce naturally?

You can buy CYA reducer (melamine) for about $50 or so a gal. from many pool stores. (One gal will remove about 20 ppm CYA from 10000 gal by precipitation) It takes more than one gallon to treat the average pool! It is cheaper to drain and refill and the melamine will make the pool like milk. If you have ever tested for CYA the liquid reagent is melamine! Do you want your whole pool looking like that?

Drain and fill ( or several partial drain and refills) until the CYA level is withing range is best...then switch to unstaiblzed chlorine and you won't have the problem again!