Make do with CH 900?

[bbrock]

Hi all. I have received so much great help from this site. With your help thus far, my pool is looking great. Tx so much.

After my partial drain/fill, done simultaneously, my CH is 900 (down from 1500). I am currently in the process of bringing my TA down from a high of 180. Today it was 150. I am shooting for a TA of 60-70. With a CH at 900, I can still have balanced water if I keep my pH in line and reduce TA to 60-70. For reference, my CYA is 50, FC 7.5, CC 0.

Is this an acceptable plan? No problems keeping CH @ 900 with balanced water, right? Pool Calculator shows that I can have a pH swing from approx 7.1-7.7 with a a TA of 60 or 70 and be balanced.

 

[JVTrain]

It looks like you have a good handle on Pool Math and that CSI is a rather important number with plaster pools, especially with high levels of CH. You should be able to manage it. It's worth trying for a while to see how it goes and if you're having troubles keeping the pH stable in that range you can address it then.

 

[JasonLion]

Yes, CH at 900 can be managed. Your plan is reasonable, though I would use an upper limit on PH of 7.6 to give yourself a little more safety margin. The key thing is to watch the PH. As long as you are methodical about that things should be alright.

CH up to roughly 1200 can be handled this way, though eventually you get to a point where there is no choice but to replace water.

 

[bbrock]

Great you two. Tx.

With regards to lowering my TA, I assume it's okay to keep lowering it to 7.0, vs. 7.2, even though the prior gives me slightly unbalanced water temporarily per Pool Math?

 

[JasonLion]

PH below 7.2 causes eye irritation for some people. Other than that, PH at 7.0 is fine in this situation.