Hello - my pool was opened for the season yesterday. Water was brown and murky. Pool service added shock and it’s no longer brown, but still very murky, and I can mostly see the bottom (couldn’t yesterday). I was going to start the SLAM process and ph reading was high (over 8). I added muriatic acid to lower and believe I overshot it. It has to be well below 7. It’s a yellow color on my Taylor test kit. Question - Do I raise it now before slamming? If so, how? Baking soda? How much? Thanks in advance!
Raise ph before SLAM?
- Thread starter krischela
- Start date
- Mar 5, 2020
- 3,052
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
- Mar 5, 2020
- 3,052
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
The 110 TA reading was after adding the acid. The reading was taken an hour after adding. Also, for what it’s worth, FC is 3 and CC is 3.5.
- Mar 5, 2020
- 3,052
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
While you are at SLAM FC, pH will be a bit higher (even though you can't see that with the test above FC 10). Once FC is down again, pH will go down again, but CO2 outgassing (at TA 110 you should have plenty of that) will have fixed the pH anyway.
I'd suggest to raise FC to 10ppm, then confirm pH again. If pH still below 7, then bring it just above 7 with borax, then continue to raise FC to SLAM-level.
What is your CYA, which SLAM-FC are you targetting?
With TA 110, it shouldn't take long for pH rise on it's own, and while at SLAM-FC, pH will be a bit higher anyway, which is why the initial pH-reduction is required, so I think you should be OK with above verification at FC 10 (where the test still works).
If you slightly overshoot FC to 11 or so, then just do the pH test quickly, don't let the sample sit with the indicator in it, FC will then slowly turn the indicator red.
I'd suggest to raise FC to 10ppm, then confirm pH again. If pH still below 7, then bring it just above 7 with borax, then continue to raise FC to SLAM-level.
What is your CYA, which SLAM-FC are you targetting?
With TA 110, it shouldn't take long for pH rise on it's own, and while at SLAM-FC, pH will be a bit higher anyway, which is why the initial pH-reduction is required, so I think you should be OK with above verification at FC 10 (where the test still works).
If you slightly overshoot FC to 11 or so, then just do the pH test quickly, don't let the sample sit with the indicator in it, FC will then slowly turn the indicator red.
Just checked again. FC at 11 and ph still low. I don’t have borax. Should I get some? And how much should I use? It’s 9pm here tonight so not doing anything until tomorrow anyway. 
I do have baking soda, but also unsure how much to use. I’ll obviously check levels again in the morning before adding anything. Thanks for the help! Really appreciate it.
I do have baking soda, but also unsure how much to use. I’ll obviously check levels again in the morning before adding anything. Thanks for the help! Really appreciate it.
- Feb 6, 2015
- 6,136
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
Your CYA should be raised to 30 for starting the SLAM Process.
At very low CYA, the chlorine will burn off quickly in the sun.
EDITED: Adjusting CYA up to 30 should only be done AFTER verifying you don't have ammonia.
Last edited:
Thanks. I wondered I I should add some. I do have the pool covered except for when adding chemicals/checking levels.
Abort mission !!!!
You'll have to forgive Gene above for being a desert dweller who doesn't close.
Us northerners need to verify there is no ammonia when opening with your current experience.
Once the test kit comes, Get 10ppm FC in there perPoolMath. Mix and test 30 mins later. If most of the FC is gone we have a quick side mission first.
Or if most of the FC remains, then raise the CYA to 30, get the PH to a low 7 and SLAM Process
You'll have to forgive Gene above for being a desert dweller who doesn't close.
Us northerners need to verify there is no ammonia when opening with your current experience.
Once the test kit comes, Get 10ppm FC in there perPoolMath. Mix and test 30 mins later. If most of the FC is gone we have a quick side mission first.
Or if most of the FC remains, then raise the CYA to 30, get the PH to a low 7 and SLAM Process
- Mar 5, 2020
- 3,052
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
It does look a bit like ammonia. But the FC 3 doesn't fit. The CC 3.5 on the other hand does - which my old eyes read this morning as TC 3.5 and didn't concern me too much. Then again, raising FC to 11 was possible, but with pH still being low.
I guess doing a formal "add 10ppm and test after 30min" is the best forward.
I guess doing a formal "add 10ppm and test after 30min" is the best forward.
It can go alot of ways and none of us are psychic.
(I'd wouldnt be able to help folks because i'd be too busy playing lotto for a living myself)
IMO ammonia is so easy to prove/disprove it makes sense to start there. Once we have reliable data.
- Feb 6, 2015
- 6,136
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I have edited my reply in post #10 to reflect the a check to verify pool doesn't have ammonia should be completed prior to adding an CYA.
"Adjusting CYA up to 30 should only be done AFTER verifying you don't have ammonia."
Thanks everyone for the help! Providing my starting numbers today. Please advise.
FC 5
CC 4.5
Ph less than 7 (still yellow)
TA 110
CYA less than 20
FC 5
CC 4.5
Ph less than 7 (still yellow)
TA 110
CYA less than 20
I should add, I’ve done nothing since yesterday where I overshot the muriatic acid and added chlorine to get to 11 (also overshot a little). Pool has been covered.
- May 3, 2014
- 58,459
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
If the pool holds FC more than 30 minutes, you do not have ammonia.
Raise the CYA to 30 ppm and start the SLAM process, as necessary.
Raise the CYA to 30 ppm and start the SLAM process, as necessary.
It does hold for longer than 30min. Should I increase ph first before starting slam?
- May 3, 2014
- 58,459
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Your TA of 110 will not allow your pH to stay at 7 for long.
Start the SLAM Process
Start the SLAM Process