Opened Pool Yesterday with Question

[Jimmy C]

Yesterday I opened the pool (took off the cover) of a IG 22000 gallon 37' Gunite pool in Round Rock, Texas. I waited until my Live Oak trees stopped their daily dumping as they do every spring.

The water was crystal clear with no algae. This was nice to see, and a good reward for keeping up the bleach and mauratic acid treatments over the winter, about 3 large jugs Bleach per month, and 1/2 gallon acid per month to keep the PH down. I also ran my pump on low speed 4 hours per day.

I dusted off my PS233 test kit (stored in dark place in my house), and here are the numbers:

FC 1.5
CC .5
TC 1.5
PH 7.8
Alk 160
Cal 220
Cya 0
Temp 74

After this test I added another large jug of bleach, and 1/2 gallon of acid....

Last Fall before shutting to pool down I had:

FC 4.5
CC 1
TC 5
PH 7.5
Alk 150
Cal 300
Cya 50
Temp 76

My question is, "Where did my CYA go, or is my test kit result inaccurate from being old?" I think I will see Marty at the pool store with a sample before I decide to add CYA. What needs to be replaced in the PS233 kit year to year?

Thanks,
Jim

[aylad]

There is a phenomenon that some of the posters (but not all) on this forum experience that is just what you described--varying levels of CYA at closing, with none on opening. Most of the time the ones that lose the CYA have algae, and the algae will break CYA down over a winter season. Other than an algae outbreak, I really can't explain why it happens, but it does. It doesn't happen in my pool, (but then again mine stays open year-round), but one of the other moderators, Watermom, has it happen in hers. Weird, huh?

If your test kit has been stored in a dark, cool place, the only thing I would worry about replacing is the dpd powder, and even then only it's clumped up or dark gray in color. The rest of the reagents should be fine.

Janet

[Watermom]

As Jan said, Every year I open to no cya - even though there is always some when I close. I never have an algae bloom, so I have no idea where it goes. I just add a startup dose each spring, and then I'm good to go for the summer. No big deal.

[Jimmy C]

Thanks for the replies. I guess I'll add some CYA with the goal of 15 ppm, and see how long that takes to show, maybe a week or so, and then eek it up to 30-40 ppm SLOWLY.

Last year at this time my CYA was >> 100 ppm after I bought this house & pool combo. I found this site by chance, and started following the recommendations including a 50% water drain / fill. The former owner used Tri-Chlor pucks. In fact I still have a bucket of those dudes. Maybe this is a good time to use these up to provide chlorination + stabilizer, and then cut back and replace with bleach once my CYA comes up where I want it. What-da-ya-think?

Jim

[aylad]

Yup, if you're gonna raise your stabilizer, you might as well use the pucks, as long as your pH doesn't nose-dive, until you get it where you want it.

Janet