Low CH in new pool


Mod Squad
LifeTime Supporter
Platinum Supporter
TFP Expert
In The Industry
Apr 1, 2007
Sebring, Florida
Take care of it now. The water will have tendency to "pull" calcium from your new plaster walls. 200-400 is what most folks consider normal......don't overshoot by much as it can lead to other issues.


LifeTime Supporter
Platinum Supporter
TFP Expert
May 7, 2007
Silver Spring, MD
You don't usually need to add calcium to a new plaster pool as the paster will naturally add calcium to the water as it cures. CH of 110 after two weeks is a bit lower than idea for this stage of curing, so you should probably add some calcium at this point, but don't add too much. The calcium will continue going up so you don't want to go all the way to your goal number just yet or you will overshoot. I would guess that there could be another 70-90 ppm of calcium coming from the curing.

The great majority of the calcium hardness increase will happen in the first three or four weeks. In another two weeks you can finish adjusting CH to your goal number.