Weekly PH Rise Question

Billtkat

Well-known member
Apr 25, 2020
99
Oro Valley, AZ
My PH seems to raise each week to where if I start Sunday at 7.2 which the CSI states "Potential to become corrosive to plaster" to 8.2 by Fri /Sat then the CSI is a "potential to be scaling" - My TA has been stable somewhere between 60 -70 as when I test @ the 6th drop it just turns red (very light) / fades to clear, to the 7th drop it is RED All other readings seems to be stable like CYA @ 30 & CH at 250 . Does the increase over the week seem OK , normal with a pool and hot tub that flows into it ?
thanks
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
41,746
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
It would be better for your to add the acid twice a week. And to modify your scheduling to turn off the spa spillover and run it just a couple times per day to keep the spa water chlorinated.

Your fill water TA is most likely high and you are adding quite a bit of fill water due to evaporation. That is how you can add acid continuously and your TA stay relatively stable.
 

Billtkat

Well-known member
Apr 25, 2020
99
Oro Valley, AZ
It would be better for your to add the acid twice a week. And to modify your scheduling to turn off the spa spillover and run it just a couple times per day to keep the spa water chlorinated.

Your fill water TA is most likely high and you are adding quite a bit of fill water due to evaporation. That is how you can add acid continuously and your TA stay relatively stable.
Thanks - Sounds like the rate of rise is not a concern however look to keep the PH more in range with a mid week adjustment.
 

Jeff J.

Well-known member
Aug 6, 2019
227
Staten Island NY
Thanks - Sounds like the rate of rise is not a concern however look to keep the PH more in range with a mid week adjustment.

You should look at adding borates. I did last summer to 50 ppm, and my PH has been solid at 7.8 all summer, occasionally drifting to 7.5 or 8.0. I haven't had to add anything but chlorine.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
41,746
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
You should look at adding borates.
Borates may help a little on the pH rise, but you will still have rising TA from the fill water. So acid will need to be added just about as often.
 

Haymarket

Member
Jul 21, 2019
21
Northern Virginia
I have a massive PH rise weekly since we turned on the SWGs. I am adding 2-3 gallons weekly, up from a half a gallon prior to the SWG turn on. TA is about 70, CYA is 60. New plaster, but the big jump started as soon as the SWGs were turned on. This is getting to be a pain and expensive to keep the PH under 8.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
41,746
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
How were you chlorinating before the SWCG was turned on?

The creation of chlorine by a SWCG does not appreciably increase the rise of pH in a pool.
 
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