Liquid Chlorine VS SWG... cheapest method?

[Sneaky D]

My T15 salt cell is gong out (after about 3.5 years) and its making me wonder how close the math is for SWG vs liquid chlorine? Seems like pre covid liquid chlorine would have been been the clear winner. With inflation and other things it seems like a lot of places want approx $10 for a gallon of 12% liquid chlorine. I think you would have to always be hunting for sales to make the math pan out. Granted it's $900 for a t15 cell now plus I figure I spend at least $100 a year on acid. So lets say that's around $400 a year on chemicals with SWG if factoring the cost of the cell. My pool is 26000 gallons so id probably need at 2-3 gallons of 12% liquid chlorine a week during the hot months AZ? What do you all think is the cheapest method? There are clear pros and cons to each. Just curious. One pool we own is 26000gal SWG the other is 12000 gal but the Wife takes care of that one since its our rental and just uses tabs.

 

[Newdude]

The math is hands DOWN in favor for a replacement cell.

A T15 in 29k gallons makes 2541.66 lifetime FC, for a cost of $0.385 per FC @ $900 plus sales tax (I did 8.8% NY because I knew it offhand).

A $6.17 gallon (with NY sales tax) of Walmart 1% is $1.81 per FC by comparison.

The T-15 is 4.71 X cheaper in the long run, albeit an upfront cost.

A similar proportion would hold true for an appropriate sized cell on the smaller pool, but divide the savings in 2 on the first cell which also needs a controller and installation. You make out on the first one, and clean UP on the replacement cells.

 

[sande005]

You might want to factor in the cost of your time, also. While testing and dumping isn't high on the list of hard-to-do chores, sourcing, loading, hauling, storing the liquid can be. And the possibly increased chances of falling into SLAM territory if the test-and-dump method gets disrupted - resulting in much more work and liquid use.....

 

[PoolGoober69]

$10 for a gallon of chlorine is pretty wild. My local Pinch a Penny has the 2.5 gallon jugs for $9.99 each. Must be hard to get chlorine out west I guess. I guess I should count myself lucky.

 

[Sneaky D]

You might want to factor in the cost of your time, also. While testing and dumping isn't high on the list of hard-to-do chores, sourcing, loading, hauling, storing the liquid can be. And the possibly increased chances of falling into SLAM territory if the test-and-dump method gets disrupted - resulting in much more work and liquid use.....

Yea, definitely things to consider. Still just curious purely from a cost basis.

 

[jark87]

sourcing, loading, hauling, storing the liquid can be.

^^^^^ This ^^^^^^

I wouldn’t have a pool where I had to keep up with liquid chlorine. I just don’t want that kind of maintenance requirement. And I just had to replace my cell. Didn’t think twice about it.

 

[Sneaky D]

$10 for a gallon of chlorine is pretty wild. My local Pinch a Penny has the 2.5 gallon jugs for $9.99 each. Must be hard to get chlorine out west I guess. I guess I should count myself lucky.

Yea, I just double checked my prices and looks like HDX is about $14.99 for 2 gallons of 10%. So math doesn't look so good for liquid chlorine especially if you already have a SWG controller. Maybe someone in the Phoenix area can chime in with how much liquid chlorine they use. I just did an estimate.

 

[KevMo]

The other aspect of going with SWG is that you effectively fix the price you pay for chlorine for the several years the cell will last. You will be unaffected by any inflation in liquid chlorine costs.

 

[Newdude]

Maybe someone in the Phoenix area can chime in with how much liquid chlorine they use.

It doesn't even matter how much you use. The 2 pack of HD bleach is $8.08 each after tax for 4 FC in your 25k gallon pool. That's $2.02 per FC and it's insane, compared to the $0.38 per FC your replacement cell will cost.

But pools average 2 to 4 ppm of daily loss, with less in the early spring/fall and more in the mid season. So maybe you'll average 3ppm loss ? $6.06 in bleach a day at HD. Even averaging 2ppm across the season, not so likely in the inhospitable desert, it's spendy.

 

[Mdragger88]

Hey @Sneaky D ,
I’m curious,
Was your last cell an “extended life” cell or just the regular one?
Do you clean your cell with acid frequently?
How long & what % do you generally run your swcg on average?
How many months per year?

 

[JoyfulNoise]

3.5 years for a cell is pretty bad. They should last a lot longer than that. Many of us can get well over 5 years out of cell and my last one lasted 8 years. But I have Pentair equipment. Unless your wedded to Hayward, you might consider going with a different equipment manufacturer.

 

[Mdragger88]

3.5 years for a cell is pretty bad. They should last a lot longer than that. Many of us can get well over 5 years out of cell and my last one lasted 8 years. But I have Pentair equipment. Unless your wedded to Hayward, you might consider going with a different equipment manufacturer.

This is why I asked about the above factors. In sunny AZ with long seasons it takes a multifaceted approach to get the best life out of the cell & reduce run times. It’s not undersized so you’d think closer to 5yrs if all the things we recommend are done.
To elaborate For the OP that means:
Maintaining slightly negative csi to prevent scale which also prevents having to aggressively clean the cell,
Considering borates,
& Running a higher cya (at least 70-80) to help prevent fc loss from the sun allowing for shorter run time and/or %
I keep noticing more folks mentioning shorter lifespans of the hayward cells compared to several years ago, folks who do all the things we recommend - this seems to coincide with the introduction of the “extended life” cells. It makes me wonder if those are just the regular cells of yesteryear and the regular ones are now subpar in someway (less coating?) although they are double the price they were not long ago

 

[HermanTX]

It doesn't even matter how much you use. The 2 pack of HD bleach is $8.08 each after tax for 4 FC in your 25k gallon pool. That's $2.02 per FC and it's insane, compared to the $0.38 per FC your replacement cell will cost.

But pools average 2 to 4 ppm of daily loss, with less in the early spring/fall and more in the mid season. So maybe you'll average 3ppm loss ? $6.06 in bleach a day at HD. Even averaging 2ppm across the season, not so likely in the inhospitable desert, it's spendy.

@Sneaky D
@Newdude is our resident expert on calculating cost of SWCG vs Liquid Chlorine.
It is all down to cost per unit of FC ppm. If the SWCG is 38 cents a PPM compared to $2.02 per PPM then it is best to purchase a new cell.
Plus you have the convenience factor of not purchasing, lugging and pouring liquid chlorine.

 

[Irishinoc]

Is the cost of running the pump included with the price of chlorine produced by the cell? My labor of pouring chlorine is free. The cost of running the pump to produce the chlorine is not.

 

[Mdragger88]

Is the cost of running the pump included with the price of chlorine produced by the cell? My labor of pouring chlorine is free. The cost of running the pump to produce the chlorine is not.

It is not- but if the cell is “oversized” as we recommend (rated for at least 2x’s the pool’s volume or larger) most only need to run their pump for around the same amount of time they were likely running previously to produce adequate fc.
For those with a VSP running as we recommend (low rpms) the price of running each day even around the clock is very small compared to a single speed pump with much shorter run times which makes a swcg an even better choice for someone with a VSP.
The other thing not calculated for is the expense of aquiring liquid chlorine on a regular basis (at an often fluctuating price).
Most need to get in their vehicle & travel to procure it which has many variable associated costs. Gas ain’t cheap.
pump run time costs & travel expenses vary greatly from area to area so one must consider their own costs to determine the true price difference between a swcg & manually dosing.
How long & at what speed are you running your pump now?

 

[Mdragger88]

One example- I have a roughly 28 mile round trip journey to aquire liquid chlorine.
This is the closest available. Today that costs me $2.60. I can only get so much in one trip so I would need to return weekly if I manually dosed. My pool is open for 7 months so that’s approximately 28 weeks.
This would cost around $72 a season just in gas. Not to mention my time.
Of course I usually combine trips but you get the idea.

 

[HermanTX]

Is the cost of running the pump included with the price of chlorine produced by the cell? My labor of pouring chlorine is free. The cost of running the pump to produce the chlorine is not.

Any time you are running the pump the FC is being produced for "free" with a SWCG, i.e. you are running the pump for some other purpose such as skimming or your cleaner, or just circulation. So the only time the pump energy cost would be additive is if you run your pump longer than you are doing now. If you really want to dig deep, the SWCG is also using some energy to run.

I think @Mdragger88 summed up that there are also many "additional" costs to using LC other than just pouring it in the pool.