Powder on plaster

[tone100]

I'm trying to figure out what this white powder is that my cleaner keeps picking up. It has about golfball size clump of white powder each week. Also the white plaster on the walls feels gritty. I don't think it's de since it seems to be coarser even after it dries out. My calcium was out of whack earlier in the summer. Around 600 and my cya was well over 100. The dot disappears almost instantly. I drained water twice and my numbers are as follows. My pool is also salt. The powder was there before converting to salt a few weeks ago.

Ch 200
Fc 4
Cc .2
Ph 7.6
Ya 90

 

[duraleigh]

My calcium was out of whack earlier in the summer.

It is really a stab in the dark but it might be calcium scale flaking off your walls now that the CH is back in range. The "texture" of your walls would seem to reinforce that thought.

 

[tone100]

I was thinking the same thing. It looks like white sand. Could it be the plaster coming off?

 

[tone100]

Any other ideas or is it calcium?