When to drain due to calcium

Sunnydaze

Silver Supporter
Mar 8, 2021
394
AZ
Pool Size
15000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello TFP brain trust. My calcium is at 525 as of today. It was 300 the same time last year. As you can guess, we have very hard water.

TA - 70
CYA - 60
Water temp - 75°

Right now, my CSI is fine but as the water warms up (it will get to 90° here) and calcium starts increasing rapidly due to the coming heat and evaporation, I think it'll be tough to keep my CSI balanced. The way I see it, I'd have to keep my ph around 7.6 - 7.7 at all times which isn't very easy because I'm also fighting high alkalinity fill water. That would probably mean adding acid every day instead of twice a week to keep it under 8 as I've been doing.

Would you recommend a drain? If even a partial? It's been in the 90's here but we have a day coming up where the temp is supposed to be 70°. Would that be cool enough for the plaster to be safe during a drain? Otherwise, i could do some no-drain water exchange.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
48,081
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
As you do not have a SWCG you should be able to manage this to 800 ppm CH or a bit higher. You might get some more waterline scale than normal. Remember, your CSI can be 0.3 and even up to 0.6 before you have any scale issues.

If the sun will shine on the plaster when dry, do the no-drain exchange if you decide to change out water.
 
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pmahosky

Active member
Jun 2, 2021
40
Austin TX
I have a similar situation but will be installing a SWG in the next few weeks. We have hard water so due to fill water my CH is 500. What level of CH do I need to either do a partial drain and refill (looking into processed water - RODI or DI if I can find it) or a no-drain exchange.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
37,976
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
I have a similar situation but will be installing a SWG in the next few weeks. We have hard water so due to fill water my CH is 500. What level of CH do I need to either do a partial drain and refill (looking into processed water - RODI or DI if I can find it) or a no-drain exchange.
This question already being tracked in this thread.

 
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