Staining in deep end of commercial lap pool

[Kaufman412]

Can someone please assist in identifying what this stain is. These stains are strictly in the deep end of our 6 lane, 25 yard, 165,000 gallon pool. The stains appeared about a month ago and haven't necessarily gotten any worse. It looks like sand at the bottom of the pool but of course when we go to vacuum or wire brush at we can't remove anything.

Chemically the pool is fine, just the calcium is a little low.

Any help is appreciated.

 

[zea3]

Hi, welcome to TFP! We need to ask a few questions to trouble shoot your problem. First we need a complete set of test results. What products do you use in this pool? Anything that contains copper or minerals? Where does the water used to top off the pool come from, municipal supply, well, or water delivery service?

 

[gwegan]

Lets do some tests.

What is the level of copper and iron in your water? What system do you use for sanitation? How about some basic test results?

1. Go purchase a bottle of vitamin C and place in a small cloth bag. Hold it against the stain for 5 or so minutes. Does that lighten the stain? Darken it? Lighten probably Iron. Darken quickly possibly copper.

2. If the above has no effect, hold a chlorine puck against it for five minutes. Lighten, Darken no effect? Lighten means the stain is organic.

If its metal you probably need to adjust your sanitation system if using metals or adjust your fill water. If its organic then you need to raise the chlorine levels higher to "burn" it out.

 

[Kaufman412]

Cl- 2.0
pH-7.6
Alk- 150
Calcium-130

Chemically we use chlorine as a disinfectant. We use CO2 to control pH. Other than that the only thing we add about every other week is a clarifier we get at the local pool store. Our water supply is from a municipal source.

 

[gwegan]

Do the tests I suggested above and take your water to a pool store that can do metals testing see what those results are. Why is your Calcium so low? Ozone or UV?

What brand of Clarifer?