One Month After Drain And Refill, My Numbers Are Way High.

[Rick Lee]

Total noobie and I've been doing a lot of reading here before posting. I live in Phoenix, just bought a house with a 10k gal. pool that's always in sunlight and hired a pro to help me for the first month. He immediately suggested a drain and refill, which I did. After a filter rebuild, a DE treatment and four weekly service visits, I decided I wanted to handle this on my own going forward. I got the AquaChek 7 test strips, a bunch of stabilizing chlorine tablets and some muriatic acid.

I am very concerned about these readings. How can they be so high one month after a drain and refill and one week after my pool guy stopped coming over?

Total hardness - 1000

Total chlorine - 10

Free chlorine - 5

pH - 7.8

Total alkalinity - 200

CYA - 150

My pool is only 4.5' deep, so there is a lot of splash and water loss when I swim, which is every day. Am I looking at another drain and refill to get this CYA under control? And what to do about the other readings? Please hold my hand. Thanks.

[chem geek]

First of all, test strips are useless. They are not accurate, especially for the CYA reading, and they cannot test Calcium Hardness (CH) which is what matters, not Total Hardness (TH). Do yourself a favor and get either the Taylor K-2006 or the TF-100 with the latter kit having more volume of reagents so is comparably priced per-test.

Fill water has no CYA in it so it is not possible for your CYA to be as high as you are measuring unless you added a LOT of stabilized chlorine. The following are chemical rules of fact that are independent of concentration of product and of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.

For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

To get to 150 ppm CYA from Trichlor tabs/pucks, you would have had to add almost 250 ppm FC cumulatively or around 8 ppm FC per day which seems very unlikely.

You should also test your fill water to see the Total Alkalinity (TA) and Calcium Hardness (CH) since with evaporation and refill these will be added to whatever is in the pool water. Splash-out or backwashing will dilute the pool water and have these parameters approach their fill water values.

I would start reading the Pool School to learn more about maintaining your own pool.

[Rick Lee]

Thanks so much. Just ordered the Taylor K-2006 test kit. I also took a sample to my local pool store on Sunday. They said my numbers weren't as bad as my test strips suggested, but that they were still high. Unfortunately, he said it's now too hot to drain my plaster pool without risking cracking and I'll just have to live with it until things cool way down.

[PaulR]

You might investigate reverse osmosis treatment. I hear there's at least one company in Arizona that does this; basically they bring a big truck to the house, spend a day pumping the water through their magic machine, and your levels of everything drop incredibly.

--paulr