Zero CYA

[BigDave]

Dichlor adds 9ppm CYA for every 10ppm FC. It also disolves very quickly unlike pure CYA.

[aylad]

If you used trichlor last season, and had zero CYA on opening this year, you might be experiencing the ammonia demand that we're seeing a lot of this year--happens sometimes when the CYA breaks down over the winter. Try testing for chlorine at night, and then test again in the morning before the sun hits the pool. If you have more than a 1 ppm loss in that time, then you have something in the water that the chlorine is battling, and you need to raise it to shock level and hold it there until whatever is there is gone. If it's ammonia, it can take LOTS of chlorine, but it needs to be done.

[Watermom]

If you decide to use that CYA instead of trichlor or dichlor to introduce stabilizer, I wouldn't add enough to add 50ppm right off the bat. Your test showing 0ppm, simply means that you have less than can be measured so that doesn't necessarily mean 0. You have to have at least 30ppm of CYA for the test to detect it. So, you may have some CYA in there -- maybe almost 30 so if you shoot for adding 50, then you'll end up with more than you want. I'd aim for adding 20 and then a week later, measure it and see where you are. You can always add more later if you are not where you want it to be.

[crispyjim]

This thread is old, but I thought I'd update it anyway.

I did go ahead with adding CYA to the pool in doses. Since 7/2 I have four readings and I recorded either 45 or 50 each time. I've consistently kept the FC between 3 and 5 ppm. CC has been <0.5 ppm. My TA has always been high (well water) but my last reading on 7/11 was 260 ppm. Direct from the well, the water has a pH < 7.0 and TA of 475.
Just for completeness, last nights readings were
pH 8+ (had a fountain running last weekend for about 10 hours and a heavy bather load)
FC 3 (added another 1.4 gal of 6% should raise it to 5.8)
CC <0.5

The pool is clear with no sign of algae. I'm using 6% bleach as my chlorine source.
I've been adding muriatic acid to bring down the pH.
I guess I'm just going to continue to dose with acid to control it.

Now, I do actually have a question. What is PF and how is it calculated? I've seen it mentioned but I have yet to find an explanation anywhere. To me, it always meant Pool Forum.

Thanks,
Jim

[aylad]

PF means pool factor--it's a number the Pool doc uses to help estimate chemical amounts. He'll be along shortly, I'm sure, to tell you how he calculates it--I don't remember--I just use the bleachcalc program when I have to calculate amounts.

Glad your pool is doing so well, hope you're having time to enjoy it this summer!

Janet

[crispyjim]

Thanks.
The Grandchildren love it.
I can't use it as much as I'd like (recent corneal transplant), but it sure helps beat the heat we've been having this summer.

Jim

[Watermom]

Thanks.
The Grandchildren love it.
I can't use it as much as I'd like (recent corneal transplant), but it sure helps beat the heat we've been having this summer.

Jim

I know exactly what you mean about the heat this summer. Having my pool was about the only thing that made it bearable when we lost our power for 7 full days and 100+ degree temps after that big storm (called a derecho) came through about 2 weeks ago.

Have fun!