My swimming pool is developing a calcium buildup on the coping tile at the waterline, what is the best method to remove it? Pool chemistry is balanced regularly and has not been a problem.


2 Answers 2


CLR or other mild acidic cleaner will dissolve the calcium, even clear vinegar.

The calcium is in your water supply and is depositing out due to evaporation. A water hardness test kit will tell you the real story. Your pool chemical dealer will have a treatment option for chealating the calcium out.

Here's an article from Taylor chemical

  • Is CLR safe for a swimming pool? My container says to wear rubber gloves and not mix with other cleaners, among other warnings, so it may not react well with people swimming in the water or the chemicals used in pool water.
    – BMitch
    Commented Mar 15, 2013 at 15:15
  • The real answer is in the second part of my answer, which is to adjust the water to stop deposition in the first place. The pool water is an incredible dilution factor. It may be necessary to drain water to even be able to put enough acid on the scale to remove it.
    – HerrBag
    Commented Mar 15, 2013 at 17:53

For years, I've spent a fortune on chemicals to clean the liner of my pool of brown stains, likely spawned by oak tree leaves falling into the pool. Chlorine and other products pushed by pool supply retailers are prohibitively expensive and were totally ineffective. Yesterday, I added 1 quart of CLR per 10,000 gallons of water in my pool. Years of accumulated brown stains disappeared within hours, and the liner's original colors were substantially restored. This pool will now sit unused for a couple more months with continuous filtration and standard chemical balancing until the water is warm enough to enjoy in June. Previously, I had to drain 21,000 gallons of water to treat the exposed liner with CLR which delivered amazing positive results, but wasted much expensive water.


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