Plaster Calcium Hardness Level?

bradthebold

Active member
Apr 20, 2020
38
Spokane, WA
Previous posts and the wiki say 250-350ppm for a plaster pool without SWG. The new pool school recommendations are 350-550ppm, which is a huge difference. Which level is correct, or why did the recommendation go up so much?
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,705
Pleasanton, CA
There is really no unacceptable maximum CH in a pool. It just makes management a bit more difficult. There are many on the forum that maintain plaster pools at much higher CH levels than 550 ppm. Also, if you have high CH fill water, you will be replacing water much too often if you go by those guidelines. You are better off just maintaining CSI in the acceptable range and when it gets too difficult to do so, then replace some water.
 

Leebo

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TFP Expert
LifeTime Supporter
Jul 21, 2011
9,944
Eastern Ohio
Previous posts and the wiki say 250-350ppm for a plaster pool without SWG. The new pool school recommendations are 350-550ppm, which is a huge difference. Which level is correct, or why did the recommendation go up so much?
Can you also point me towards the WIKI article as I'd like to update it................
 

RMcGirr83

Gold Supporter
Nov 19, 2018
900
Tuscola, TX
Can you also point me towards the WIKI article as I'd like to update it................
About 1/2 way down the page
"Keeping the CH around the minimum recommended value, ~ 200ppm" and "A plaster pool without a SWG should have CH levels between 250ppm and 350ppm if possible. With a SWG, CH should be kept between 350ppm to 450ppm."
 
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bradthebold

Active member
Apr 20, 2020
38
Spokane, WA
Ok, I just don't want to run into scaling issues. I am draining 2/3 of my water now to resolve high CYA and will have to add Ca to get the hardness up to whatever the goal is.