Output of gritty substance

migraine · Jun 13, 2010

I have an above ground pool ( aprox. 20,000 gal) with a Compu-Pool SWG and a Hayword Sand Filter. The SWG is new to the pool this year. I am having problems with the system outputting a lot of gritty substance I believe to be sand. I did not have this problem until I installed the SWG. Any suggestions as to what is causing this?

Mike

JohnT · Jun 13, 2010

Welcome to TFP.

Could be calcium. Post a complete set of test results for best advice.

migraine · Jun 13, 2010

What type of test are you needing?

JasonLion · Jun 13, 2010

Take a look at What we need to know to answer your questions.

migraine · Jun 13, 2010

Free chlorine = 1ppm, PH = 7.2, Total Alkalinity = 120 ppm, & Cyanuric Acid = 30-50 ppm

JohnT · Jun 13, 2010

migraine said:
Free chlorine = 1ppm, PH = 7.2, Total Alkalinity = 120 ppm, & Cyanuric Acid = 30-50 ppm

Calcium Hardness is the key number we need.

migraine · Jun 14, 2010

I'll try to get a sample to the local pool supplier this week.

migraine · Jun 18, 2010

Okay, went by my local pool supply store and had my water tested here are the results: FAC = 2.5; TAC = 2.5; PH = 7.6; TA = 120; Calcium Hardness = 250; CYA = 50; & Phosphates = 500. I hope this helps. Let me know if there is additional information needed. thanks.
Mike

JasonLion · Jun 20, 2010

It might be calcium, or it might be sand. There are a couple of different ways of checking. The most reliable is to gather a little of the substance and put a few drops of muriatic acid on it. If it is calcium it will foam up, while sand won't really react at all. Another way to check would be to lower the PH to 7.2. If it goes away at the lower PH then it is calcium.