Question about SWG run time

[VinnyinNJ]

We're a week away from having our AG pool installed. I opted for an Aquatrol SWG for the chlorine generation vs bleach/liquid chlorine.

Since I don't have real world experience yet I'm playing around with Pool Math and it looks like to generate 2 PPM chlorine I could run the SWG at 55% for 14 hours or 75% for 10.5 hours; I realize that this is just playing around and real world is going to be different. I know these cells wear out and my question is - Is it better to run the cell at a lower percentage for longer periods or is it better to bump up the percentage to have a shorter run time for cell longevity? Or does it matter at all? I do want to keep the cell usage below 100% so that it's not pushing itself all the time.

Paying a little extra for electricity per month to keep the cell longer may be worth it vs paying $600 in 2 or 3 years for a replacement cell. I estimate the cost of the cell vs using liquid chlorine is going to be about the same if I get a 3 or 4 year lifespan out of the cell.

Any thoughts?

 

[Newdude]

The cell depletes from chlorine production, not pump runtime or %. Any equal maths use the same amount of production. 100/12 or 50/24 both use 12 hours of your expected 10k hour life (for most units).

You upsize for that reason. A 'properly sized' unit for your pool needs to run 24/7 to produce your daily expected FC loss. It loses 24 hours of life a day. A 2X unit only needs to run 12 hours to produce the same FC, effectively doubling its life. If the oversize was cost proportionate, it wouldn't matter, but it's only a small cost to upgrade for a big gain in lifespan. That also saves electric costs with less runtime to produce the same FC

 

[VinnyinNJ]

The cell depletes from chlorine production, not pump runtime or %. Any equal maths use the same amount of production. 100/12 or 50/24 both use 12 hours of your expected 10k hour life (for most units).

You upsize for that reason. A 'properly sized' unit for your pool needs to run 24/7 to produce your daily expected FC loss. It loses 24 hours of life a day. A 2X unit only needs to run 12 hours to produce the same FC, effectively doubling its life. If the oversize was cost proportionate, it wouldn't matter, but it's only a small cost to upgrade for a big gain in lifespan. That also saves electric costs with less runtime to produce the same FC

Thanks! I was suspecting it doesn't matter but wasn't sure.

Although I read to upsize the SWG, I couldn't see spending another $800+ for an IG SWG. The price difference to upgrade from IG to IG larger wouldn't be as bad IMO. Based on what you are saying I should (or hope to get) about 10K hours out of the cell which could give me approximately 2 1/2 to 4 years depending on how long it needs to run to regenerate the chlorine loss. I guess this is where real world comes in!

Thanks again!

 

[Newdude]

Based on what you are saying I should (or hope to get) about 10K hours out of the cell which could give me approximately 2 1/2 to 4 years depending on how long it needs to run to regenerate the chlorine loss. I guess this is where real world comes in!

Think of the seasonal loss as a bell curve. Early and late season you'll barely need any production and mid season is the most. You will adjust the unit to match that weeks loss of wherever you are in the season. It's a short season up here and an even shorter peak season. You should be very happy with the cells life.

 

[VinnyinNJ]

Think of the seasonal loss as a bell curve. Early and late season you'll barely need any production and mid season is the most. You will adjust the unit to match that weeks loss of wherever you are in the season. It's a short season up here and an even shorter peak season. You should be very happy with the cells life.

OK, great explanation! Wasn't thinking of the use being a bell curve....

 

[markayash]

OK, great explanation! Wasn't thinking of the use being a bell curve....

I used to worry about cell Life then decided doing that is like buying a nice couch and not letting anyone sit on it

 

[Tcadwall0]

I think it is just as important to maintain your CSI at a slightly negative level. My cell is 1.5 yrs now, and I haven't had to do any maintenance to it yet (has not required cleaning). I probably would keep it more neutral if I didn't have a FG pool. Not sure it will last longer, but at least I am not having to give it chemical baths.

 

[VinnyinNJ]

I used to worry about cell Life then decided doing that is like buying a nice couch and not letting anyone sit on it

I agree, not too worried but I'm a numbers guy and like to forecast out to get a general idea. You should see my retirement spreadsheet!!!!

 

[VinnyinNJ]

I think it is just as important to maintain your CSI at a slightly negative level. My cell is 1.5 yrs now, and I haven't had to do any maintenance to it yet (has not required cleaning). I probably would keep it more neutral if I didn't have a FG pool. Not sure it will last longer, but at least I am not having to give it chemical baths.

So far I have only tested my tap water for CH and it is coming in around 60 so at the low end of the spectrum, I'm hoping that means no scale to worry about. As far as the other parameters ... to be determined... I'm slightly concerned about using muriatic acid as I have never used it ever but I'm sure with proper experience and handling it'll be OK. I plan on testing the water before filling to have the borax, baking soda and acid available to start the balancing.

 

[proavia]

So far I have only tested my tap water for CH and it is coming in around 60 so at the low end of the spectrum, I'm hoping that means no scale to worry about. As far as the other parameters ... to be determined... I'm slightly concerned about using muriatic acid as I have never used it ever but I'm sure with proper experience and handling it'll be OK. I plan on testing the water before filling to have the borax, baking soda and acid available to start the balancing.

Chances are you aren't going to need borax or baking soda. But you will need muriatic acid and chlorine.

Post the pH, TA and CH of your fill water.
Have you become familiar with PoolMath and the FC/CYA Levels?

 

[markayash]

I agree, not too worried but I'm a numbers guy and like to forecast out to get a general idea. You should see my retirement spreadsheet!!!!

Are you in accounting? My wife's a CPA and is the same say.

I am the opposite, when my pH is high I dump a little acid and retest tomorrow.

 

[VinnyinNJ]

Chances are you aren't going to need borax or baking soda. But you will need muriatic acid and chlorine.

Post the pH, TA and CH of your fill water.
Have you become familiar with PoolMath and the FC/CYA Levels?

Yes, I used to use the old Pool Math and have downloaded the new Pool Math. I understand that my water's PH will drift up with the SWG so you may be correct in that I don't need borax and baking soda. I'm sure if I dig in my garage I'll find the old stuff I used for my pool... I already found a small amount of stabilizer and my DE filter is sitting there, it's going to be retired!

 

[VinnyinNJ]

Are you in accounting? My wife's a CPA and is the same say.

I am the opposite, when my pH is high I dump a little acid and retest tomorrow.

No, not in Accounting but I have about 3 years into an Electrical Engineering degree and then life took over. I tend to prepare and research and do it all over again! I've been plotting our retirement path since 2016 and I have 2 more years to work (actually 22 months but who's counting... me!)

 

[Tcadwall0]

Actually, borates is one of the things I didn't mention above that I also do. I do the old borax+acid method since it is easy enough and I can get them locally. That also helps buffer the localized pH increase in the salt cell reducing the wear and build-up.