CH for attached spa with SWG

csmyrnos

Member
Aug 12, 2018
5
Redding, CA
Hi all... Long time lurker and just recently took over maintenance of my pool from the pool guy. I have a pebble-tec pool with an attached spillover spa. I have an IC40 SWG on order that should be here in a week or two. My question relates to the CH level I should be at. In the ABC‘s of pool water chemistry, the recommendation CH level for a pool w/spa is 100-150 (to reduce foaming) but everything I’ve read regarding SWG’s suggest a much higher CH level. I’ve been pretty consistently at a CH level of 100 (TF-100 test kit) using liquid chlorine as my sanitizer but will I need to raise it significantly with the SWG? Will that cause issues with foaming if I do? The lowest recommended CH level in the manufactures literature is 200 ppm.

Latest pool math numbers if this helps:
FC 3.0
pH 7.4
TA 70
CYA 40
CH 100

Thanks In advance!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
12,960
Northern NJ
Welcome to TFP.

The ABCs say:

A plaster pool without a SWG should have CH levels between 250 and 350 if possible. With a SWG, CH should be kept between 350 to 450. Calcium helps fiberglass pools resist staining and cobalt spotting. If you have a spa you might want to keep CH at at least 100 to 150 to reduce foaming.
If you have a stand-alone spa you want to keep the CH at least 100 to 150. If CH is less then that you can get foaming. Higher CH reduces foaming. You can keep your CH greater than 150.

With a plaster pool and SWG raise your CH to at least 250. If you don’t have high CH fill water that will eventually raise your CH then CH of 350 is recommended to keep your CSI in a range where scale does not form on the SWG.

See Recommended Levels - Trouble Free Pool
 

csmyrnos

Member
Aug 12, 2018
5
Redding, CA
Ah OK... The way I was reading the ABC’s was a lower CH number prevented foaming... Not the other way around. Once I get my SWG installed, I’ll raise the CH and get everything else dialed in per pool math. Thanks for the advice!