No Drain Acid Wash

Drew80

Well-known member
Feb 26, 2013
221
Austin, TX
I just replied to the other thread. Copying here with some details for context.

My builder skipped town right as my pool was finishing and I didn't know enough about chemistry to balance my water properly. So I had staining. Lots of white patches on blue plaster. After a year, I started researching what to do about it.

I ended up doing a no-drain acid wash with Jack's Magic Copper & Scale Stuff. It made a HUGE difference. Make sure you bypass your heater or it will eat right through the copper line. And make sure you leave the pump running continuously while doing the treatment - movement is very important for Jack's to work. I ended it after about 5 days and my plaster looks fantastic. Some of the staining has come back, but only in spots where I have something sitting against the plaster (ie, chairs in the beach area).

One thing to note - the stains on your plaster are likely very high in calcium, so your hardness it going to go through the roof. I ended up with a hardness around 800 and had to drain my pool to bring it down.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
19,788
Northern NJ
One thing to note - the stains on your plaster are likely very high in calcium, so your hardness it going to go through the roof. I ended up with a hardness around 800 and had to drain my pool to bring it down.
It is not that the stains are high in calcium. What the acid wash does is dissolve the plaster surface and with it the stains if they are on the surface. Your high CH is all the dissolved plaster from the acid wash. You reduce the thickness of the plaster and weaken the plaster to improve the cosmetic look of the pool.