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Thread: There is white cement plaster in my cartridge filter

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    There is white cement plaster in my cartridge filter

    My in-ground 24,000 gallon pool is 51 years old and it has never never been re-plastered and leaks only about 15 gallons per day. Over the years the cement had dissolved exposing sharp sand grains that hurt the grand kids feet. Sp 3 years ago I "polished" the white plaster with #50 grit diamond concrete polishing pads. A lot of white slurry was created during the grinding process which I vacuumed/shoveled out.

    The I started pool back up and it worked great. Only thing I noticed is I have 3 small rust spots where rebar leaches through. Last year I replaced my sand filter with a cartridge filter. I use a Kreepy Krawly and when I clean the cartridge I am getting a small amount of white cement. It is the white cement "dust" that plugs the cartridge after 2-5 days. I keep the Ph about 7.0 to 7.2.

    Does anyone have idea on how to cut down on cement leaching?


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    alanpaul's Avatar
    Join Date
    Aug 2010
    South Florida

    Re: There is white cement plaster in my cartridge filter

    Jerry, Welcome to TFP!

    Have you read Pool School (at the Upper Right)? It's all about pool care and the simple side of the chemistry you need to know to keep your pool sparkling, clean and in good condition, at the lowest possible cost. It also explains the online Pool Calculator, designed to take all the guesswork out of using and balancing the chemicals in your own personal, particular pool.

    In response to your post:
    First, your pH would be too low in most people's opinions. Do you have a reason to keep it below the recommended 7.4 - 7.6? That's a hair more acidic than many people find comfortable, and it may be having a deteriorating effect on your plaster if you have kept the pH low for an extended period of time.

    From elsewhere on the internet: On the pH scale, zero indicates extreme acidity, 14 indicates extreme alkalinity, and 7 indicates a neutral state. The recommended pH-range for a swimming pool is between 7.2 and 7.8.

    In a swimming pool, water of insufficient alkalinity can begin to dissolve the surface, creating a rough texture(a perfect breeding environment for pool algae growth).

    Second, when you used your sand filter, did the sand become hard and 'solid' like cement, and is that what prompted you to change to a cartridge filter?

    Third, after sanding, did the surface of the pool have an opportunity to 'cure' before adding water and chemicals for daily use?

    Jerry, if you have a high quality water test kit and are able to post your test results, that will enable members to assist you with this and any other issues you may be experiencing, now and in the future.

    Because they all are variables in the maintenance of every pool, please also include your specific pump and filter info, if possible, along with your method of chlorination, and your location. Do you use any type of heating? (Note the bottom-line signatures of many members as examples of pool info).

    We look forward to your post of test result numbers, and addressing your issues.

    Alan in Wellington, FL - near West Palm Beach
    15,200 gal IG, painted plaster, 1988; 200 SqFt cartridge filter, 2013; 1.5 HP 1-speed pump (uprated), 2005; heat pump, 2005;
    soon to repair (dead) SWG AquaRite T-15 cell, 2005, and replace (dead) suction-side cleaner, 2005.
    Almost everything died this winter 2012-'13, and I know we shouldn't complain... but, Arrgh!

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