Large Amounts Of Calcium On Pool Walls
We have a two month old salt water pool with beadcrete plaster. About 3 weeks ago we noticed a buildup on the polaris that looked like sand particles. Then the polaris bag started filling up with a white sand material daily.
We heated the spa and after getting it was unbearable. The plaster was so rough it would cut your skin. We could brush piles of sand from the walls.
We had a pool company doing the chemicals, so we checked the levels and the PH was above 8.2, the CL was above 3.0, and the alkalinity was very high. The pool company had been adding acid weekly but was not bringing it down. We added acid and it would come down for a day or two and then go back up.
We live in Houston, TX and nobody else is having an issue. We got a few cold nights but nothing else has been different.
How do we get rid of the calcium buildup and get our plaster feeling normal again. Pool company is stumped and everybody we bring out just keeps saying to add acid.
Nothing seems to be working and we can't even use our brand new pool. HELP!
Thanks for the question Sandee
My first question is did you recently have the pool replastered? The question says "we can't even use our brand new pool" so can I assume it is a freshly plastered pool? If it is a new pool with fresh plaster, you can expect some settling of the new plaster and some will come off. Many times this can happen if the pool was filled too quickly and the plaster didn't have a chance to cure completely.
2nd, I'd like to have your calcium readings. "High" is relative and means different things to different people. The alkalinity reading would help as well. For a salt pool you don't want to have the calcium any higher than 250ppm. The best range is between 150 - 250ppm. When I had my pool route in Arizona the fill water calcium level was very high, sometimes around 400ppm. I would need to drain and refill some pools every other year to keep it down.
pH doesn't increase without outside influences either. This can be through granular chlorine (which has a pH
level of 12), high pH fill water, or splashing around with causes the carbon dioxide (CO2) to burn off, thus increasing the pH.
How big is your pool and how much acid was being used? This is important because 1/4 gallon of acid in a 5,000 gallon pool is much different than 1/4 of acid in a 50,000 gallon pool.
I'd encourage you to test your fill water. Calcium hardness can't increase without an outside influence, mainly either calcium chloride, high fill water hardness, or the use of granular chlorine.
When the question says acid was added to the pool but "it" didn't come down, which one were you trying to reduce, the pH or alkalinity? Acid is used to reduce both the pH and total alkalinity but it depends on how to add it.
The high pH level and the high alkalinity level can contribute to plaster erosion. But again, I'll need the alkalinity reading to be sure.
Adding more acid to the pool a misguided hope that will clear it up, without a good plan and understanding of what is causing the readings to be off is completely wrong. You're wasting your time and money.
So, it could be simply the pH and alkalinity need to be adjusted, which is a simple process. I wouldn't worry about the chlorine being 3.0 or near that. I keep the YMCA pool between 3.5 - 4.5ppm and it's fine.
If the calcium is higher than 300ppm, you'll need to reduce it. The only way is to drain 1/3 - 1/2 of the water, refill, and balance out the chemicals. Get me the the alkalinity and calcium reading, the size of your pool, and how much acid is being used.
Do you have a sand filter and if so, is it shooting back back into the pool? And when you sweep the sides and bottom of the pool does plaster come up? It sounds like it could be a simple fix but I would need just a bit more information.
To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Calcium Hardness" category.
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Hope this helps and have a great Summer.