The Numbers Game - TA and CH levels for new plaster


Silver Supporter
May 22, 2016
Orlando, FL
We're very excited to have a new quartz surface in our pool. It was filled one week ago and I have been doing tests and balancing twice a day using my TF100 to maintain the levels. I'm having a hard time deciding what numbers to use.

The NPC start-up guide (from here wants:
TA - 80
CH - 150 (minimum, added slowly over 28 days not to exceed 200 ppm)

The plaster product spec sheet - Premarbelite Mix (PMM) Marquis Quartz (
TA - 100-120
CH - 250 - 400, (but then the warranty page says don't add calcium for 30 days, and then only if it is below 200

TA - 70-90+
CH - 250-350

My last pool test on the Pool Math app was
FC - 4
pH - 7.5
TA - 95ish (do you count the drop when it ceases to be green/grey in color, or the one where it turns reddish, or the one where it turns red)
CH - 175ish (same thing with the color interpretation)
CYA - under 20
Temp - 87

So, what numbers should I aim for TA and CH to keep the CSI and new plaster happy? Also, I watched a video from NPC rep Greg Garrett who said that "carbonate" alkalinity should be used, not TA. He said that if you subtract 1/3 of the value of your CYA (about 6 for me) from the TA reading (95 for me), you get the carbonate alkalinity (90ish for me). How does that impact the CSI value?


PS - I won't tell you what the contractor did to the water at start-up, scary


Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
Tucson, AZ
For all the tests you count the drops until the last one causes no further color change and don't count that last drop. For TA the sample will be fully red/pink.

I don't think you need to adjust any of them at this point. The TA and CH may still go up from the plaster. Just balance with the pH to keep CSI neutral. And forget about that adjusted TA stuff, just use the CSI in PoolMath. ;)


Mod Squad
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
This is how I see my TA test-

first it goes dull red- count that drop!....
then it goes kinda hot pink- count that drop!...
then it goes BARBIE HOT PINK!- count that drop!...
another drop and the wild hot pink doesn't change anymore... don't count that drop!

Maddie :flower:
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Silver Supporter
May 22, 2016
Orlando, FL
Thanks- just saw the Speed Stir in the signature- very cool. Will be getting one of those.

Jb Lizzl- when you say the TA and CH may still go up from the plaster, does that means the water is pulling calcium from the plaster to balance itself? I remember the NPC saying that you should run positive on the CSI. Should I worry about that?

Thanks so much. Will be making a donation to TFP!
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