Too much alkaninity casue high level of cyanuric acid

[Mike B]

recently my alkalinity was 20 ppm. ph 6.2 Chlorine was 5.3 and I was told to add 40 lbs of ALKA +. I did so and then the Alkalinity was too high. When I went back to the pool store, they manager it was too much and he gave me chemicals to lower it. This week it is still about 180 ppm. When I went in to the pool store the clerk said my cyanuric acid was too high. 2 weeks ago my acid level was 0 and now it's too high. He did not give me the readings. He said to drain the pool about a foot below the skimmers and than add water and retest. My question is I added the 40 lbs at one time could that cause the rapid increase? Or could it be something else?

[chem geek]

You were probably given the wrong quantities to add. Adding it all at once makes no difference. Also, there is NOTHING that the pool store could have given you to directly lower the Total Alkalinity (TA). TA is only reduced through a combination of lowering the pH, aerating the water, and adding acid to keep the pH low as described in this post. As for the Cyanuric Acid (CYA), dilution via partial drain/refill or more frequent backwashing is the only way to lower it (and this will lower your TA and CH as well).

In the future, use The Pool Calculator to figure your dosages of chemicals.

Richard