Tradeoffs with Cell Size?

[Alex_H]

I have a "small" by Florida Standards pool, 10,800 Gallons. Single speed pump (and a spare motor -- long story) so won't be switching out for 8-10 years.

Most of my gear is Hayward, so I looked at their stuff. When I looked online, the AquaRite AQR3 (up to 15,000 gallons) made sense. On the other hand, plenty of sources say to get the bigger cell. I'm not against different brands, just trying to simplify my setup so I don't need to get bleach (and bleach stains)...

Any suggestions?

I assume I can hook it to the same timer as the pump in parallel. If and when I switch to a Variable Speed pump, a real decision will have to be made, because our Polaris Floor System will have issues then too.

Thanks in advanced!

 

[Jimrahbe]

Alex,

When it comes to salt cells in can be pretty easy to be Penny wise and Pound foolish..

Running a 15K cell at 100% will produce about a .4 ppm increase in your FC per hour. This means you will have to run your pump for about 8 hours per day to keep your pool chlorinated.. assuming it uses the average of 3 ppm of FC per day.

On the other hand, running a 40K cell at 100% will produce about a .93 ppm increase in your FC per hour. This means you would only have to run the pump just over 3 hours to produce the same 3 ppm of FC.

Even if you don't care about the cost to run the pump, a 40K cell will last more than twice as long as a 15K cell in your case, as you can run the 40K cell at a much lower output.

With a single speed pump, you can wire the pump and the cell to the same time clock.

Thanks for posting,

Jim R.

 

[BasicTek]

When I purchased my Hayward SWG the 40K was on sale (and had a $100 rebate) and only cost me about $100 more than the 15K not to mention the recommendations from everyone to oversize for the reasons Jim said. Looking at amazon they are currently selling the 40K system for just over $200 more than the 15K. There's no way that the 15K system could be a better deal unless they start selling it around $400.

I don't need a 40K for my pool (but at the time for $100 more...) and I run mine only 4 hours a day at 20% in the summer 5% now in the winter (so if I wanted I could drop it to 1 hour) . I'm pretty sure my cell will die from some other cause other than using up it's chlorine limit. I seem to have a hyper over producing t15 cell but it never hurts to turn your cell % down and run it for less time....

 

[Alex_H]

Thanks so much. No interest in being anything foolish, which is why I'm here.

Status Quo, I run that my pump for 8 hrs/day in the winter, 10 hrs/day in the summer. Floor system filtration, cool water features, poor homeowner decisions, whatever.

So if I put in the top cell, I manually reduce the percentage to lower my FC/hour?

Assuming I'm not going to reduce the hours of the Pump/Chlorine, I just want the biggest and reducing the output so it lasts longer?

That's the part I couldn't figure out. So if I get a 60K rated one, and run it at 20% power, it should work for a number of years?

That sounds great to me!

 

[needsajet]

Nice to meet you via TFP

Not sure what models you're considering, but let's say it's the T-cell-9 vs. T-cell-15. They output 0.7 lbs/day and 1.4 lbs per day respectively (if run for 24 hrs at 100%). They will both last for about the same number of total operating hours, so if the T-cell-15 costs less than twice as much as the T-cell-9, you're ahead in the long run. The larger cell is usually nowhere near double the cost, which is why larger cells work out to better economics.

Here's a useful description of the nitty-gritty, in case you want a deeper dive on the question: Economics of Saltwater Chlorine Generators

 

[Alex_H]

Nice to meet you via TFP

Not sure what models you're considering, but let's say it's the T-cell-9 vs. T-cell-15. They output 0.7 lbs/day and 1.4 lbs per day respectively (if run for 24 hrs at 100%). They will both last for about the same number of total operating hours, so if the T-cell-15 costs less than twice as much as the T-cell-9, you're ahead in the long run. The larger cell is usually nowhere near double the cost, which is why larger cells work out to better economics.

Here's a useful description of the nitty-gritty, in case you want a deeper dive on the question: Economics of Saltwater Chlorine Generators

Thank you so much!!!

That is the part I couldn't figure out from web research. The Cell life is "number of pounds of chlorine" -- but they aren't sold that way, they are sold based upon "how big of a pool" and to some extent "FC/hr" -- that link was terrific.

I will stay away from the "low end" versions (like the plug in version instead of direct wired in version) -- but I'm thinking that the InyoPools white label one with a 60,000 cel might be a viable choice.

Thanks!!!

 

[Alex_H]

They will both last for about the same number of total operating hours, so if the T-cell-15 costs less than twice as much as the T-cell-9, you're ahead in the long run

Okay, this is the part that confuses me.

Operating Hours vs. Amount of Chlorine.

Unless I want to put the Chlorinator on a different time (and my times tend to get confused over time), so I'd rather not, the 10,000 hours will be used up in 3 - 3.5 years.

Running the 15,000 Gallon Cell (T-cell 9 or equivalent) at 100%, it will use 10,000 hours AND the lifetime chlorine cap in 3.5 years.
Running the 40,000 Gallon Cell (T-cell 15 or equvalent) at 30%, it will use the 10,000 hours up in 3.5 years but the "lifetime chlorine" level will last 7-10 years.

Will I be throwing away a 30% used T-cell 15? Or will I get 7-10 years of the T-cell 15 and 30,000 hours because it's at 30% power?

That's the part I can't figure out. I'm thrilled to be $100-$200 more for a more powerful cell if it lasts 2x-3x as long, that's a no brainer. However, if I'm buying an overpowered cell, and I need to replace it in the same time period, it seems more efficient to run a T-cell 9 at 100% than a T-cell 15 at 30%.

That's the question.

Is it "total chlorine" or "total hours operated" or is it "first one used up?"

Thanks in Advanced!

 

[mknauss]

The cell only operates when it is generating chlorine. So if you have it set for 50% for 10 hours, the cell operated for 5 hours.

So your calculations above are incorrect. A 15k rated cell in your pool will need to run ~18 hours each day at 100% during the summer. The 40K cell would need to run ~6 hours each day at 100%. So it will last ~3x longer than the small cell.

Take care.

 

[needsajet]

Yep, Marty has you covered

The "SWCG % setting" times "SWCG timer hours" equals "operating hours"

Using Trouble Free Pool Care (TFPC), people here tend to get 7 or 8 years out of 2X oversized cell, with a few going 10 years or more.

 

[Alex_H]

Thank you guys!!! All set now, thanks so much!!!