high Ph won’t come down

ktiz81

New member
Jun 30, 2019
1
Michigan
Hi,

i didn’t know whether to post this in the water chem section or here.

but I have a new hot springs spa with the freshwater salt system.
Current water parameters:
ta 70
Ph 8.4
Fc 5
Salt 1800
Ch 50

everything is in balance according to manufacturer specs except I can’t get my ph to not climb after aeration.

Do I keep driving the Ta down even more?

I started with a very high Ta, and have brought that down into range, but additions of acid bring TA down more, and ph does not stay down.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
7,816
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
@cowboycasey, what do you think?

ktiz, aeration causes pH-rise. I would think in a tub that principle gets magnified...
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
4,593
Fletcher, OK
hot tubs send PH through the roof :)

I kept my TA down at 40 or 50 and it helped a lot but you will still need to add acid weekly if not more depending on how much you use it... Mine had a small circulation pump so it only used the big pumps when I was in it and that would kick the PH real fast...

With a high TA fill water you will be adding acid a lot to keep it down, is what it is...
 
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SallyD

Member
Oct 8, 2020
8
Chaska, MN
Hi,

i didn’t know whether to post this in the water chem section or here.

but I have a new hot springs spa with the freshwater salt system.
Current water parameters:
ta 70
Ph 8.4
Fc 5
Salt 1800
Ch 50

everything is in balance according to manufacturer specs except I can’t get my ph to not climb after aeration.

Do I keep driving the Ta down even more?

I started with a very high Ta, and have brought that down into range, but additions of acid bring TA down more, and ph does not stay down.
Just for another reference point, I too have a brand new hot springs spa with the freshwater salt system. Mine is behaving the same. I just keep pushing the TA down, but I try to do it a little at a time so it doesn't end up too low. Learned something here though - aeration increases pH. The support guy from the dealership didn't tell me that of course. Thanks cowboycasey and Dirk
 
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Roaddogmm

Member
May 26, 2020
16
Cary, NC
hot tubs send PH through the roof :)

I kept my TA down at 40 or 50 and it helped a lot but you will still need to add acid weekly if not more depending on how much you use it... Mine had a small circulation pump so it only used the big pumps when I was in it and that would kick the PH real fast...

With a high TA fill water you will be adding acid a lot to keep it down, is what it is...
I do the same thing. I actually have very low TA in my tap, and was increasing it to 80 per manufacturing recs. My PH would stay high, and I'd have to add muriatic acid every 2 or 3 days to keep it down. Gradually my TA has been driven down to about 40, and I find that my acid requirements are much less now, I can go for a week before it creeps from 7.4 back up to 7.6. I think on the next fill I'll prob just leave it alone.

Note, I do have borates at 50 which is supposed to help with buffering of PH i believe.