Why does Pool School recommend TA 60-80 in "Water Balance for SWGs" ?

Jump to latest Follow Reply
F

feuGene

0
Jul 18, 2017
18
Indian Harbour Beach, FL
https://www.troublefreepool.com/content/138-water-balance-for-swg-saltwater-chlorine-generator

There's no explanation there of why the 60-80 range is recommended.

My SWG manual suggests 80-120.

I'd like to increase my Calcite Saturation Index (currently at -0.41), and increasing my TA seems like a good way to do it.

I'm at 70 now so I could obviously go up to 80 without contradicting any of these recommendations. But that would only put me at -0.33, still outside of my SWG's recommended range of -0.3 to 0.3.

So I'm inclined to push my TA up to 90 or 100, which would put my CSI at -0.26 or -0.21, respectively; but I'm hesitant to go against the recommendations of the Pool School. So I thought I'd ask, why is 60-80 recommended there?
 
To reduce pH rise from the SWCG operation. No problems going outside those ranges if you want to or need to for your particular circumstances. Just be aware that you may have to work more to maintain your pH if you do.
 
I can’t answer why 60 to 80, but my TA sits at around 110- 120 and keeps my ph steady at 7.6 to 7.7 all summer. Everything I read it says to not adjust TA just for numbers. If for a specific reason then go ahead.
 
It's a lot easier to let your PH rise to 7.6 then it will be to maintain your TA where you want it. The TA should be left where it sits once you get your PH as stable as possible. You could be setting yourself up for a circle of adding baking soda to raise TA and adding MA to lower PH. Any PH 7.8 and under is within range.
 
Most equipment manufacturers simply parrot the NSPF, APSP and other association's recommended levels. There is no science to their recommendation other than how it relates to boiler water and cooling tower applications....most pools are not water boilers so what they recommended is simply wrong.

You base your TA in a plaster pool on what level produces the most stable pH value and keeps your CSI in the appropriate range. For an SWG pool, you want your CSI to be slightly negative to avoid calcium scaling inside the cell. So a CSI of -0.3 to 0 is just fine. pH and TA are the largest drivers of CSI changes so I would suggest you simply keep your pH higher and you'll be fine.

What pH do you normally shoot for? That has a lot to do with TA and CO2 outgassing which is the biggest contributor to pH rise and stability.
 
Well, my pH seems to be always in flux. I've owned this pool (my first pool) for 4 months now and it feels like I'm always having to add acid. (Yesterday was the first time I ever adjusted TA.) So, my pH definitely will rise enough to put CSI in a good range, but then it'll very soon after rise enough that I have to bring the pH back down, likely to outside of a good CSI range. I generally shoot for the low end of the pH range, like 7.4 (not 7.2, so as not to push the limits with CSI), just because that will give me more time before the next inevitable pH rise, so that I don't have to be adding acid every time I test.

I'm making it sound worse than it is; of these 4 months, I had a house-sitter do what the local pool store told them, for a total of about 6 weeks, and then these past few weeks I've just barely gotten things back together after Hurricane Irma. So, I've got a limited track record here, but I do have the visceral feeling that my pH rises annoyingly quickly.

If finding the right TA level for my pool is a key to providing me a stable pH, I definitely want more info on that. What can I read? (a Pool School article?) Or what empirical process can I use to determine the right level?

Many thanks!

BasicTek said:
It's a lot easier to let your PH rise to 7.6 then it will be to maintain your TA where you want it. The TA should be left where it sits once you get your PH as stable as possible. You could be setting yourself up for a circle of adding baking soda to raise TA and adding MA to lower PH. Any PH 7.8 and under is within range.
Click to expand...

JoyfulNoise said:
Most equipment manufacturers simply parrot the NSPF, APSP and other association's recommended levels. There is no science to their recommendation other than how it relates to boiler water and cooling tower applications....most pools are not water boilers so what they recommended is simply wrong.

You base your TA in a plaster pool on what level produces the most stable pH value and keeps your CSI in the appropriate range. For an SWG pool, you want your CSI to be slightly negative to avoid calcium scaling inside the cell. So a CSI of -0.3 to 0 is just fine. pH and TA are the largest drivers of CSI changes so I would suggest you simply keep your pH higher and you'll be fine.

What pH do you normally shoot for? That has a lot to do with TA and CO2 outgassing which is the biggest contributor to pH rise and stability.
Click to expand...
 
My PH was rising so much I had to add acid twice a week with TA at 70-80 and I started raising the TA when it dropped to 60. They told me to leave the TA alone and maintain PH at 7.6 - 7.8. Now My PH is usually around 7.8, I add acid about once every 2-3 weeks, and my TA is at 50. I maintain my CSI around -.1 to -.3.

If I tried to keep my PH at 7.2/7.4 I would get back in the loop again of adding baking soda and adding MA.
 
It's counterintuitive but trying to keep the pH at 7.4 causes the pH to rise.

Keep the pH at 7.8 and the TA at whatever keeps the pH stable.

You should find that you have almost zero pH rise.

Maintaining the CYA at 60 also helps.
 

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply