Added Borates, ph still drifts up

stbasil

LifeTime Supporter
Jul 12, 2010
43
Wimberley TX
Questions for some of you pool chemistry gurus:

I have always had to add lots of acid to keep my pH down to 7.6 - 7.8, so I thought I would try adding borates. I lowered the pH to 7.6, added about 33 lbs of boric acid a couple of weeks ago, so I should be around 50ppm borates now. My chemistry is as follows:

TA: 80
pH: 8.4
CYA: 70
CH: 550? (I think my chemistry for this is too old, need to re-supply)
Salt: 3500
FC: 5

However, I have still had to keep adding acid to get the pH down to around 7.8. So, I thought I would just let the ph drift up to see if it would stabilize somewhere, and it seems to slow its rise around 8.4, which seems too high. However, the TFP poolcalc indicates a Calcium Saturation Index of 0.27, and says the pool is balanced. My water is clear, and if it is "balanced", do I really need to keep adding acid to get my pH down to below 8? I have read here that I could lower my TA by aeration, which might help the pH stabilize at a lower number, but is that really necessary since the TA does not seem to be excessively high? Makeup water comes from a municipal supply, which is sourced from the Trinity aquifer in Central Texas and has a hardness of around 25 grains per gallon (about 420 ppm) and pH around 8.2.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,259
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
What is the TA of the fill water?
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,259
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
If you are adding much of that fill water, your pH will rise regardless of borates.
 

stbasil

LifeTime Supporter
Jul 12, 2010
43
Wimberley TX
My question remains, however: is a pH of 8.4 OK as long as the CSI is in the balanced range? Supposedly, that CSI value says that I should not have problems with scaling.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,259
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
A pH of 8.4 can exacerbate the scaling of your SWCG. It can also irritate eyes and some people may feel skin irritation.
 

stbasil

LifeTime Supporter
Jul 12, 2010
43
Wimberley TX
Thanks for your inputs! I think I will aerate to lower my TA some more, and just plan to keep the pH at around 8.0.
 
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