grey spots in bottom of pool

Total hardness and calcium hardness in pool water.
Scale, calcium buildup, hard water and scaling problems.

grey spots in bottom of pool

Postby hk » Mon 03 Aug, 2009 07:51

I have grey spots in the bottom of my pool. I would like to know what these spots are and can they be removed. I tried brushing with a wire brush but not effect on the spots.

grey spots in bottom of pool

Postby elf » Mon 03 Aug, 2009 23:58

could be stain from metals in water starting or black algae starting.
if you have a plaster pool you can take a tab and rub it on the stain and see if it starts to come off, if yes black algae which can be taken off with different black algae treatments depending on what color plaster you have as some can stain colored plaster as they sit on the stains to remove them.
If the tab does nothing then its metals in the water along with PH probably being to high. You need to use a sequestering agent/metal remover that comes in 1qt bottles or 1/2 gallon and add to your pool along with lowering your PH level to 6.5-6.7 and scrub your pool a few times a day until gone. Then readjust your PH level back to 7.2-7.4.
You could also get a PVC pipe with a fitting at the end that could trap muriatic acid in it, so you can hold this over the spot and pour the acid into the PVC pipe which will sink to the bottom where the stain is. This would be like acidwashing this small area removing the stain with some brushing after and readjusting PH after depending on how much was needed.
This is for only plaster, pebble-tech pools.
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Grey spots in bottom of pool

Postby geeman » Fri 07 Aug, 2009 10:22

Is this a plastered pool? If so, when was it plastered?

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