Correct numbers for SWG pool

MarkHoop

Well-known member
Aug 16, 2022
134
Ontario, Canada
Pool Size
22000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Zodiac LM3-24
Hi Folks, Loving the site and hope to get many years of useful info from all of you. I have had issues in the past with my SWG pool and am told that my chemistry is off. I have read the "Water Balance for SWG's" article and it seems to be contradictory with regards to the "ideal numbers. Here is what I see:

Salt - as per manufacturers specs
CYA - 70-80
FC - 5-7
TA - 60-80
CH - less important but 50 min. and less than 400 (I have a vinyl pool)
Borates - 30-50

If all of the above are correct my question is with regards to pH. One part of the article states 7.2-7.8 and not lower but to add Muriatic to lower it back to 7.2-7.5. Later it says that the range should be 7.6-7.8. What am I shooting for ideally or am I over-analyzing the pH?

Just want to be clear as I don't want to be told that I am messing up again.

Thanks,
 
It is a bit confusing in that article, I agree.

I think the "lower it back to 7.2 - 7.5" is meant for TA reduction (add acid to reduce pH and TA, then let pH rise by aeration which doesn't change TA, repeat until TA is at target).

pH in the higher 7s will, in combination with TA in the 60-80 range, lead to slower pH-rise.
 
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It depends in the end on how high in TA your fill water is.

If the fill water is low in TA, then TA should stabilise in the 60-80 range, and you don't want to lower pH too much, as it will eventually drive TA too low (below 50), making a baking soda addition necessary. In this case pH should stabilise around 7.8 to 8, and only very moderate acid addition may be required from time to time.

If your fill water is high in TA, then each time you top up evaporation losses, your TA will rise again, speeding up pH-rise again. In this case, pH will from time to time need to be reduced into the 7.2 - 7.5 range to compensate for the TA-rise from the fill water.
 
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Well another Canadian winter is passed and getting ready to open our pool. I am fully on-board with the TFP process for 2024 and look forward to the results. I have read the "How to" on pool opening and appreciate that once the pool has been circulated for a few days and tests completed that I will add Cl as required. I will then balance all of the rest of the chemicals but my question is if there is a preferred order for these? Do I get CYA in balance after Cl and then work on the others? I am clearly a Type A and want to ensure that I don't mess this up so want to be prepared in advance as it will be about a week before opening....:oops::oops:

PS - I plan to utilize PoolMath app for my directions as well.

Thanks as always
 
 
Much appreciated !! 👍
 
I am clearly a Type A and want to ensure that I don't mess this up so want to be prepared in advance as it will be about a week before opening....:oops::oops:

Don't sweat it...you got this :)

Once you're 'open', check your FC and make sure it is in-range for your current CYA levels. If its not (and it's more likely to be low than high) then you risk Algae, and we don't want that. A gallon of 12.5% will pop you up about 6ppm, and its always better to be at the top of that range than the bottom, especially when you're opening up and you may have been a little below the range for a while. Supplement with Liquid Chlorine as required until your SWG is up and running.

Talking of SWGs, obviously salt is also a concern, and needs to be high enough for the salt-cell to operate, if it's not, get that up to where it needs to be too. With winterization draining a chunk of water which is refilled mostly by rain, I know my 'static' chemicals are all down by up to 25% come opening. Adjust as necessary, might take a day or two to fully circulate. Don't overthink it :)

Once your SWG is humming along with your LC/CYA in balance, you can add CYA to where you want it.

PH. TA, CH are more 'long term' and comfort levels. PH should be in the ballpark, someone here told me once not to chase the needle there - 7.2-7.8. 7.6 is probably 'perfect', but don't sweat it if its 7.4. TA works as the buffer, so it really depends on your fill water. If (like me) most of your fill is the rain, your TA is probably on the low side, especially at open. Baking soda is super-cheap, and will get your TA where you need it.

CH is probably your least concerning - some say it's not important at all in a vinyl pool. I've also read a couple articles that say it can help in the longevity of the liner. Mine is on the low side, and I've not seen any real reason to spend a bunch of money to raise it, especially as I have a heater/SWG myself so avoiding scaling is good.

PoolMath is an awesome tool. Spring for the annual sub if you can. Log your test results, log your additions, and then review your next set of results with where you expected things to be, versus where they are. My pool is '25,000' gallons...but it's really not quite 24. I'm not sure the level of precision is a big deal...but I'm type A too, so of course it is ;) The 'effects of adding' and suggested additions functions are great - again, don't chase the needle, but if you want to get your TA up, PoolMath will tell you how much you need to do it - and then maybe split that in half, wait a day or two, retest and repeat.

Biggest piece of advice I got - Don't try to fix everything all at once. Relax. The pool isn't going to go green in 2 hours. If in doubt, ask...people around here are super smart, and super helpful.
 
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Don't sweat it...you got this :)

Once you're 'open', check your FC and make sure it is in-range for your current CYA levels. If its not (and it's more likely to be low than high) then you risk Algae, and we don't want that. A gallon of 12.5% will pop you up about 6ppm, and its always better to be at the top of that range than the bottom, especially when you're opening up and you may have been a little below the range for a while. Supplement with Liquid Chlorine as required until your SWG is up and running.

Talking of SWGs, obviously salt is also a concern, and needs to be high enough for the salt-cell to operate, if it's not, get that up to where it needs to be too. With winterization draining a chunk of water which is refilled mostly by rain, I know my 'static' chemicals are all down by up to 25% come opening. Adjust as necessary, might take a day or two to fully circulate. Don't overthink it :)

Once your SWG is humming along with your LC/CYA in balance, you can add CYA to where you want it.

PH. TA, CH are more 'long term' and comfort levels. PH should be in the ballpark, someone here told me once not to chase the needle there - 7.2-7.8. 7.6 is probably 'perfect', but don't sweat it if its 7.4. TA works as the buffer, so it really depends on your fill water. If (like me) most of your fill is the rain, your TA is probably on the low side, especially at open. Baking soda is super-cheap, and will get your TA where you need it.

CH is probably your least concerning - some say it's not important at all in a vinyl pool. I've also read a couple articles that say it can help in the longevity of the liner. Mine is on the low side, and I've not seen any real reason to spend a bunch of money to raise it, especially as I have a heater/SWG myself so avoiding scaling is good.

PoolMath is an awesome tool. Spring for the annual sub if you can. Log your test results, log your additions, and then review your next set of results with where you expected things to be, versus where they are. My pool is '25,000' gallons...but it's really not quite 24. I'm not sure the level of precision is a big deal...but I'm type A too, so of course it is ;) The 'effects of adding' and suggested additions functions are great - again, don't chase the needle, but if you want to get your TA up, PoolMath will tell you how much you need to do it - and then maybe split that in half, wait a day or two, retest and repeat.

Biggest piece of advice I got - Don't try to fix everything all at once. Relax. The pool isn't going to go green in 2 hours. If in doubt, ask...people around here are super smart, and super helpful.
Awesome...you guys ROCK!!!! Hey, I feel young.... 😂
 
I have read the "Water Balance for SWG's" article and it seems to be contradictory
So arguably the biggest problem for TFP is we are looking after several different types of pools, world wide. With different styles, finishes, fill water parameters and climates, it's hard to always nail the one size fits all thing.

Ask anytime something doesn't quite line up for you and we'll happily hatch your own specific plan.
 
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So arguably the biggest problem for TFP is we are looking after several different types of pools, world wide. With different styles, finishes, fill water parameters and climates, it's hard to always nail the one size fits all thing.

Ask anytime something doesn't quite line up for you and we'll happily hatch your own specific plan.
Understood, thanks
 
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