Would You Raise the CH?

[Toxophilite]

My plaster is now on the 5th month. My weekly tests are always about the same, other than slowing been lowering TA to where it's finally seemed to settle on wanting to be, at least, the last 4 tests.

On my CSI, I'm 90% of the times in the hundredths, one way or the other, .05 to -.05 swings. When test that with Pool Math for a hypothetical ideal CH of at least 350, I show it would put me more in the tenths range on CSI. Overthinking the importance of CSI? Or, of CH? What is best CH for pebble finish in the long run, or, back to CSI management better approach?

Yesterday's Test:

FC = 3.5
pH = 7.8
TA = 80
CH = 200
CYA = 40
CSI = 0.05
WT = 91 degrees

 

[Rancho Cost-a-Lotta]

Looks good to me. CH will rise slowly and you'll probably be in a good spot when water temps drop in fall/winter. What's impressive is that you achieved a TA of 80 with 260 fill water. I'm guessing you've added a bit of muriatic acid.

 

[Toxophilite]

Thanks! Yes, TA was left with me at 120 by PB. Been MA additions about every 3rd day since. That has not slowed down one iota. But, now that TA seems to have found a home and appears to be stabilizing, I'm ready to get some of these long-term numbers done and over and just concentrate on the short-term pH and chlorine work. CH has never really been an issue, other than PB left me at 130, which I quickly raised, and been near or at the 200 ever since me raising it. Most stable parameter I have.

So, with my limited chemistry knowledge other than HS level, my TA stabilized but additions of fill water and aeration will likely keep my acid demand going in the long run?

 

[Rancho Cost-a-Lotta]

So, with my limited chemistry knowledge other than HS level, my TA stabilized but additions of fill water and aeration will likely keep my acid demand going in the long run?

With fill water TA at 260, it will be a constant battle. Mine TA is at 130. I run my spa spillover consistently during the summer to drive up pH, which allows me knock TA down with MA.

Consider borates. Borates will slow down pH rise (more time between doses) but will require more MA to drop pH. No cost savings, but less frequent maintenance.

 

[Toxophilite]

With fill water TA at 260, it will be a constant battle. Mine TA is at 130. I run my spa spillover consistently during the summer to drive up pH, which allows me knock TA down with MA.

Consider borates. Borates will slow down pH rise (more time between doses) but will require more MA to drop pH. No cost savings, but less frequent maintenance.

Thanks, again! I was just recently thinking, if my TA is staying within bounds, when does my acid demand from new plaster start to settle down, why not already getting there? I only add LC and use pucks when CYA gets low. Well, I totally forgot about my fill water being what it is!!! Tunnel-thinking. I should have remembered to factor that and just never did. Thanks!