Co2 Injection

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
I'm considering a CO2 injection system to control my pH as I'm finding I'm adding acid quite frequently. I'm wondering if anyone can share their experience with it? I was looking at the Hayward one but I'm open to other options
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,027
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
CO2 injection does not reduce TA. So be sure to check if your fill water is high in TA and if that is the source of your pH rise.
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
CO2 injection does not reduce TA. So be sure to check if your fill water is high in TA and if that is the source of your pH rise.
My alkalinity is very low (20 ppm) and I havent been adding sodium bicarb. I have a SWG and my chlorine is sometimes higher than needed on the lowest setting (likely because my pool is quite small) so that is constantly raising my pH.
 

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,696
NW Ohio
Dealing with pH rise with a TA of 20 is extremely unusual. What are you using to test?
 

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,696
NW Ohio
Given the choice between believing some very unusual water behavior or that a ColorQ is spitting out bad data, I'm leaning heavily towards the latter.

Do you have any liquid based tests to confirm these readings?
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Given the choice between believing some very unusual water behavior or that a ColorQ is spitting out bad data, I'm leaning heavily towards the latter.

Do you have any liquid based tests to confirm these readings?
I dont have another test kit to compare to, but I suspect my colorq is accurate because it does show consistent readings on my hot tub and it reflects the changes I make when I add acid. I brought my pH down from 7.9 to 7.5 last night and by morning it was back up to 7.7
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,704
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The TA reagent of the ColorQ has had several bad batches shipped out. LaMotte technical support will confirm this if you call them and give them the lot id of the reagents you have. The ColorQ also doesn’t measure CH very accurately as it is more of a total hardness (TH) reagent and not a true CH test. You can purchase an inexpensive TA test or simple pool water testing kit that includes TA to cross check your ColorQ.

Consistency, precision, and accuracy are not the same things. Any test can be consistently wrong with very precise results if the underlying test chemicals or equipment are compromised in some way. ColorQ’s are known to go bad with age and give bad results. This is why TFP doesn’t typically recommend them or trust their results much.
 
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JamesW

TFP Expert
Mar 2, 2011
23,909
I brought my pH down from 7.9 to 7.5 last night and by morning it was back up to 7.7
Highly unlikely if the TA is really 20. We're missing some key information. Do you have an acid feeder?

What is the CSI?

What are the chemistry readings

What is the chemistry history?

What is the pool size and type?
 

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Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
The TA reagent of the ColorQ has had several bad batches shipped out. LaMotte technical support will confirm this if you call them and give them the lot id of the reagents you have. The ColorQ also doesn’t measure CH very accurately as it is more of a total hardness (TH) reagent and not a true CH test. You can purchase an inexpensive TA test or simple pool water testing kit that includes TA to cross check your ColorQ.

Consistency, precision, and accuracy are not the same things. Any test can be consistently wrong with very precise results if the underlying test chemicals or equipment are compromised in some way. ColorQ’s are known to go bad with age and give bad results. This is why TFP doesn’t typically recommend them or trust their results much.
I did take a sample to the pool store to double check on the TA and CH as I my kit is about 3 years old now so I wanted to get a reference. Since my TA was only 20 ppm and I've not added any sodium bicarb (I got tired of fighting with it causing my pH to rise even more) i cant imagine there would be any rise in my TA levels.

I'm an ex public health inspector and used to use the Taylor kit, but our health department did some research and decided to switch us to the Lamotte because they were not satisfied with inconsistency that came from using a visual colour comparison chart. I was resistant at first but I wouldnt go back to the Taylor now as I really appreciate the digital reading
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Highly unlikely if the TA is really 20. We're missing some key information. Do you have an acid feeder?

What is the CSI?

What are the chemistry readings

What is the chemistry history?

What is the pool size and type?

I've got a 10000 litre fiberglass pool with a SWG and hayward cartridge filter.

My FAC is currently 2 ppm, CC 0.1 ppm, CH 200 ppm, TA 20 ppm.

I have a solar cover but I've been leaving it off lately as my temp was getting too high (90 degrees). When I had it on the FAC was climbing higher than needed even on the lowest setting (up to 8 ppm).

The pool has only been up and running for a month now.

I fought with high CC for the first week (even after draining and refilling) because my pool builder had filthy water sitting stagnant for 3 weeks in it during construction. I did a SLAM and took care of it and it has been decent since then.

The only noticeable issue has been a greasy waterline which I suspect is from sunscreen as I slather my pale Scottish kids heavily with zinc sunscreen
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Correction- it is 10 000 gallons not litres
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
I'm wondering if the SWG is just pumping out more chlorine than this small pool needs causing my pH to keep going up. I am burning off the chlorine right now because I've got the solar cover off but there's still a large amount that would be getting generated
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
8,624
Central California
Pool Size
12300
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Just reduce the runtime of the SWG if turning it down still results in too much FC.
 

Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
Just reduce the runtime of the SWG if turning it down still results in too much FC.
It is the right amount provided I've got the cover off and it is sunny as it is currently 2 ppm FAC. I'm adding acid daily though ...
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
37,027
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
I'm wondering if the SWG is just pumping out more chlorine than this small pool needs causing my pH to keep going up.
That does not happen. The pH does not appreciably rise from the creation of chlorine by the SWCG.
 
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Prickly

Well-known member
Jul 8, 2020
100
Kelowna
Pool Size
31000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-9)
That does not happen. The pH does not appreciably rise from the creation of chlorine by the SWCG.
Even in the absence of acid injection?
 

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