Is my SWG insufficient for the size of my pool?

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sande005 said:
Using the numbers in this thread, that means currently for 8 hrs, the pump is costing you $3.12 per day. Augmenting the generator with liquid might add $1-3 per day (wild guess). Going with a VS, using the above 24/7 would be $1.32 per day - and give you enough Cl to not go green.
Perhaps $400-900 per pool season to offset the cost of the new pump, until you hit break even.
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Yeah, so it sounds like my options are:

1. Replace salt cell with one that can handle my pool size w/ the same pump and run 8 hrs/day. Cost: whatever it costs for the salt cell and labor to replace (or, free if I'm able to convince the pool guy since he messed up?)

2. Don't replace anything, continue running at 8 hr/day, supplement with liquid chlorine. Cost: an extra $1-3/day for chlorine (depending how much I can find it for).

3. Replace pump with VS pump so I can run 24 hr/day keeping the same salt cell. Cost: whatever the cost would be for the VS pump and installation, then assuming I'd get similar wattage as ajw22 mentioned above I'd save ~$60/month.

4. Replace the salt cell AND pump with a VS. Cost: parts and installation for both salt cell and VS pump, then save ~$60/month compared to now in electricity. Or more than $60/month, since with a bigger salt cell I may not need to run the pump 24/7. (Or - salt cell is free since pool guy messed up :) ).

So it really comes down to how much a salt cell and/or VS pump would cost me. And also what the pool guy is willing to do. I'll have to do some research on that.

A few remaining questions:

I may be ignorant, but the salt cell looks super easy to swap out (I remove it to inspect it...) - is swapping it out for a different one really that easy? Seems like it's something I can easily do myself.

If I change the salt cell, can I still keep the same controller box (the AquaRite 900)?

Haven't looked too much at the pump, probably not as easy as changing out the salt cell - but is that also something relatively easy that I could do myself?
 
Jahlon said:
1. Replace salt cell with one that can handle my pool size w/ the same pump and run 8 hrs/day. Cost: whatever it costs for the salt cell and labor to replace (or, free if I'm able to convince the pool guy since he messed up?)
Click to expand...

You will have to run a 940 cell at 80% for about 12 hours for 2PPM/day or 18 hours for 3ppm/day.

So 8 hour/day runtime will not be enough with a 40K cell.

Jahlon said:
3. Replace pump with VS pump so I can run 24 hr/day keeping the same salt cell. Cost: whatever the cost would be for the VS pump and installation, then assuming I'd get similar wattage as ajw22 mentioned above I'd save ~$60/month.
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What heater do you have?

You probably cannot run at my wattage without a few other tricks.

Jahlon said:
I may be ignorant, but the salt cell looks super easy to swap out (I remove it to inspect it...) - is swapping it out for a different one really that easy? Seems like it's something I can easily do myself.
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Yes, it is easy DIY.

Jahlon said:
If I change the salt cell, can I still keep the same controller box (the AquaRite 900)?
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Yes.

Jahlon said:
Haven't looked too much at the pump, probably not as easy as changing out the salt cell - but is that also something relatively easy that I could do myself?
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Depends if you can do some electrical connections and PVC plumbing.
 
ajw22 said:
You will have to run a 940 cell at 80% for about 12 hours for 2PPM/day or 18 hours for 3ppm/day.

So 8 hour/day runtime will not be enough with a 40K cell.
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Is there something better than a 940? Would that be overkill?

Running at 80% still seems kinda high to me, and I'd like reduce pump time as much as possible.

Also, could you teach me how you're doing the math or what specification you're looking at in the salt cells? From Hayward's website they gave a rating in lbs/day (0.98 for the 920). How do you get ppm per day from that?

ajw22 said:
What heater do you have?
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I don't have a pool heater.

ajw22 said:
You probably cannot run at my wattage without a few other tricks.
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What sort of tricks?

Any idea what wattage I'd realistically be able to see with a VS pump?

Another thing I just thought of - I recently bought a solar cover (though I haven't opened it up yet). Would this reduce the breakdown of chlorine, and therefore help my situation by requiring less additional chlorine or pump runtime?
 
Jahlon said:
Is there something better than a 940? Would that be overkill?
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No, the 940 is the largest cell Hayward makes.

You can put two cells on your pool to generate more chlorine and need to run your pump less.

Pentair and Circupool make 60K cells.

Jahlon said:
Running at 80% still seems kinda high to me, and I'd like reduce pump time as much as possible.
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That's the best you can do with one Hayward cell.

Jahlon said:
Also, could you teach me how you're doing the math or what specification you're looking at in the salt cells? From Hayward's website they gave a rating in lbs/day (0.98 for the 920). How do you get ppm per day from that?
Click to expand...

Use PoolMath app or Pool Math on the web.

1722799107339.png
Jahlon said:
I don't have a pool heater.
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Good, that will not restrict your pump then.

Jahlon said:
What sort of tricks?
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Getting your plumbing as flow efficient as possible.

Jahlon said:
Any idea what wattage I'd realistically be able to see with a VS pump?
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Without a heater you should be able to run a SWG with 200-250 watts.

Jahlon said:
Another thing I just thought of - I recently bought a solar cover (though I haven't opened it up yet). Would this reduce the breakdown of chlorine, and therefore help my situation by requiring less additional chlorine or pump runtime?
Click to expand...

It may a bit.
 
ajw22 said:
No, the 940 is the largest cell Hayward makes.
Click to expand...

I'm guessing I'm stuck with Hayward, since the Aquarite 900 is also a Hayward? Or could I mix/match salt cells with the controller box?

ajw22 said:
Without a heater you should be able to run a SWG with 200-250 watts.
Click to expand...

Wait, 200-250 W is less than the 500 you're getting... What am I missing? (Or is it because you have a heater and I don't?)

Do I need to factor in the wattage of the actual SWG (not the pump - I guess what the salt cell and the controller uses) - or is that pretty much negligible?
 
Jahlon said:
I'm guessing I'm stuck with Hayward, since the Aquarite 900 is also a Hayward?
Click to expand...

Yup.

Jahlon said:
Or could I mix/match salt cells with the controller box?
Click to expand...

Nope.

Your pool company should have sold you a Pentair IC60 system.

Jahlon said:
Wait, 200-250 W is less than the 500 you're getting... What am I missing? (Or is it because you have a heater and I don't?)
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ajw22 said:
My VS pump runs 24/7 at 1400 RPM at 200 watts. That is $1.32/day or about $40/month.
Click to expand...

I don't think I ever mentioned 500 watts although my pump uses that much when at a hiogher speed for skimming and cleaning.

Jahlon said:
Do I need to factor in the wattage of the actual SWG (not the pump - I guess what the salt cell and the controller uses) - or is that pretty much negligible?
Click to expand...

SWG pulls about 2 amps at 120V or 240 watts.
 
ajw22 said:
Your pool company should have sold you a Pentair IC60 system.
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🙃

ajw22 said:
I don't think I ever mentioned 500 watts although my pump uses that much when at a hiogher speed for skimming and cleaning.
Click to expand...

You're right, I apparently made 500 watts up... You said 200.

ajw22 said:
SWG pulls about 2 amps at 120V or 240 watts.
Click to expand...

I'll have to factor that in as well when comparing a single speed pump vs VS pump running all day.



Also, in case anyone is curious - I sent a message to the pool company about it, and in their reply they said:

"Good morning,
Your pool is approximately 24k gallons according to the standard equation for gallonage. 20x40x4x7.5 = 24k.

(Length x width x average depth x 7.5)
(Average depth is maximum depth / 2)"

The bolded part above is the part I believe they messed up...why would average depth be just the max depth divided by 2? Basically, they're averaging 0 and the max depth... Every other calculator I've seen, and my own logic, says it should be the average between the shallow end depth and the deep end depth. That would be an over 10k gal difference! Using their mix/max depths (which were slightly different than mine): 20x40x6x7.5 = 36k. (6 ft would be average of 4ft and 7.5ft rounded up).

I am very annoyed...
 
Jahlon said:
"Good morning,
Your pool is approximately 24k gallons according to the standard equation for gallonage. 20x40x4x7.5 = 24k.

(Length x width x average depth x 7.5)
(Average depth is maximum depth / 2)"

The bolded part above is the part I believe they messed up...why would average depth be just the max depth divided by 2? Basically, they're averaging 0 and the max depth... Every other calculator I've seen, and my own logic, says it should be the average between the shallow end depth and the deep end depth. That would be an over 10k gal difference! Using their mix/max depths (which were slightly different than mine): 20x40x6x7.5 = 36k. (6 ft would be average of 4ft and 7.5ft rounded up).

I am very annoyed...
Click to expand...

Your Pool Service is not very smart with math.

Even if your pool was 24K a 25K cell is still undersized. The 25K cell would need to be run at 90% for 24 hours a day to give sufficient chlorine.
 
ajw22 said:
Your Pool Service is not very smart with math.

Even if your pool was 24K a 25K cell is still undersized. The 25K cell would need to be run at 90% for 24 hours a day to give sufficient chlorine.
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Yes agreed... This is just totally wrong. I wish I had a better understanding of all this back then, but I had a million other things related to the move going on... Plus, that's the whole point of hiring "professionals". They had good reviews, so I trusted they knew what they were doing.

I'm running some numbers to figure out the best thing to do... I really appreciate all your help so far. Would you be able to help me with a few more questions?
  1. Does the output level I set my SWG affect the wattage it uses? (e.g. if I turn it up to 100% it uses the full 240 W, 50% it would be 120 W, etc.)
  2. Where did you get the wattage for my SWG (from your previous post)? I found this (page 3) which has the amp range for each cell, with the T-9 as 2.3-6.7.
  3. Is there a rule of thumb/recommendation for how much chlorine I should be able to generate per day? To your point above, I don't want something that will just barely keep up - if I'm losing 3ppm/day, and my SWG can generate 3 or 4ppm/day (maxed out), that is obviously not ideal. Should I shoot for something more like 7ppm (that's about where I'd want my total FC level to be according to this, if my CYA is around 70)?
 

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Jahlon said:
  1. Does the output level I set my SWG affect the wattage it uses? (e.g. if I turn it up to 100% it uses the full 240 W, 50% it would be 120 W, etc.)
Click to expand...

Nope. Cells run for a %. Your Hayward cell has a 180 minute cycle time. If you set it for 50% it runs for 90 minutes then rests for 90 minutes. When it runs it generates at 100%.

Jahlon said:
  1. Where did you get the wattage for my SWG (from your previous post)? I found this (page 3) which has the amp range for each cell, with the T-9 as 2.3-6.7.
Click to expand...

It is in the Installation Manual specs. 2.3-6.7 is the amps on the 24V transformer side that powers the cell.

Jahlon said:
  1. Is there a rule of thumb/recommendation for how much chlorine I should be able to generate per day? To your point above, I don't want something that will just barely keep up - if I'm losing 3ppm/day, and my SWG can generate 3 or 4ppm/day (maxed out), that is obviously not ideal. Should I shoot for something more like 7ppm (that's about where I'd want my total FC level to be according to this, if my CYA is around 70)?
Click to expand...

You only need to generate your daily FC loss.

In NJ with CYA 70-80 you will lose 2-3ppm/day.
 

Attachments

  • 092540_RevG_585e.pdf
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ajw22 said:
hayward.com

AquaRite w/TurboCell, for Pools up to 25,000 Gallons (Open Line)

The World's #1 Salt Chlorinator. AquaRite salt system is the convenient alternative to conventional chlorine - bringing the very best in soft, silky water with no more red eyes, itchy skin, or harsh odors.
hayward.com hayward.com

Click to expand...

Ok, now I know I'm being super annoying...where are you seeing the amperage or wattage in here? Ctrl+f'ing everything and can't find it...
 
ajw22 said:
Yup, same regardless of cell size.
Click to expand...

Ok, so then here's my little trade study. Let me know if you think I'm getting all this right (if you feel like taking the time :)).

(Couldn't attach it as an image for some reason, so included it as an attachment).

Looks like my main priority should be switching to a VS pump. It would be significantly less expensive in energy (~$240/month less). With the TCELL925 I'd have to run it at 100% for the full 24 hrs/day, but that should be me a little over 3 ppm/day. Maybe a little wiggle room to reduce it if I don't need quite that much.

Longer term, after I use up the TCELL925 I could replace it with a TCELL940, which could generate 3 ppm/day at only 60%.

Edit: Ok, the attachment didn't work either...just copied and pasted below from my excel sheet.

Pool specs:
Length (ft)40.0
Width (ft)20.0
Depth (shallow)4.0
Depth (deep)7.5
Depth (average)5.8
gal/ft^37.5
Volume (gal)34500.0
water lb/gal8.34
Water Weight (lbs)287730.0
FC Daily Loss (ppm/day)3.0

Single Speed Pump, TCELL925 SWGSingle Speed Pump, TCELL925 SWGVariable Speed Pump, TCELL925 SWGSingle Speed Pump, TCELL940 SWGVariable Speed Pump, TCELL940 SWG
FC Max Daily Output (lbs/day)0.980.980.981.471.47
Output Setting100%100%100%100%60%
Pump Daily Runtime (hr/day)824241424
FC Daily Increase (ppm/day)1.13.43.43.03.1
Pump Power Use (W)150015002501500250
Pump Daily Energy Use (kWh)12.036.06.021.06.0
SWG Power Use (W)240240240240240
SWG Daily Energ Use (kWh)1.925.765.763.365.76
Electricity Cost ($/kWh)$0.27$0.27$0.27$0.27$0.27
Monthly Energy Cost ($/month)$112.75$338.26$95.26$197.32$95.26
 
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