Collin

Hello all, I just joined the forum in hopes that I could find some answers from someone about the white substance on the bottom of my pool. We had it installed last year and it is a inground pool free form pool with a pebble finish.I have the water tested at least three times a month and the usual issue is with an elevated PH. I usually add about a gallon of acid and 15 lbs. of alkalinity plus every 2 weeks per the test results and the pool stores advice.I have the floor sweeping system and about every three days a pile of white ( sand like substance ) starts to build up in the corners of the pool .I can easily vaccum it up but in about 2 days it starts to come back.I went down to the bottom where some had collected up and put it in a bottle to have the pool store test it.They don't have a clue what it is! My filter is the kind that has the three cartridges in it that have to be removed and cleaned and then replaced every so often.I cleaned them good and hoped it would clear up.The water itself is always very clear and has never been cloudy.The pool stores advice was to drain the pool and start over.I don't see the purpose in this if the water is testing good. Any advice on what this could be and how to remove it? Thanks