Is this limescale, calcium, spalling, efflorvescence on flagstone? How do I remove

[cagmkt71]

I'm new to the forum, thanks for advice in advance.

I have a retaining wall on one side of the pool. It has a flagstone face and I'm getting a little weaping of moisture and a build up of limescale or whatever the white mineral build up is. I've attached a picture to show the problem. Any ideas on how to address this? I've tried pool store scale removers, CLR and diluted MA with no luck. I literally have to scrape the rock like build up with a scraper and then use a pumice stone on the tiles. Just not sure what to use on the flagstone.

 

[JamesW]

Is there groundwater behind the wall?

 

[wellsnlisa]

Do you have one of the recommended kits? Can you post a full set of test results? I had something similar on a stacked stone wall where our spa spilled over into the pool. It turned out our calcium hardness level was way too low for a plaster pool. The water was leaching calcium from the stone. I cleaned it off with a stiff plastic bristle brush and a 3 parts water to one part muratic acid solution, rinsing often. Then I added enough calcium to bring the water's CH up to recommended levels for a plaster pool. (I used Pellets of Fire ice melt that I ordered from Amazon.). It never came back.

 

[cagmkt71]

yes, we just had a lot of rain so it's a little worse than usual

 

[JamesW]

I think that it's efflorescence due to ground water seeping through the wall. The solution would be to improve drainage to prevent excess ground-water behind the wall.

 

[First Pool Judith]

I had some calcium leaching (not as much) on a couple of flagstones along the edge of the pool. I used a pumice stone to scrape it and then a 5" stainless steel brush. It came off very quickly and easily.