Ready to switch to SWG, have questions

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DrewLG

DrewLG

Gold Supporter
May 31, 2022
684
Santa Cruz Mountains, CA
Pool Size
8000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
I've been using a Hasa Liquid Feeder to meter liquid chorine into my pool. Works great, no issues.

But now its tank is cracked. And I see from other posts that this is a known defect, and that Hasa is providing the excellent customer service that they're known for and replacing tanks free of charge. But as long as I have to mess with my chlorination anyway, I'm thinking about switching to a SWG.

I have questions:
  1. I gather that running the cell at 100% shortens its life. But is everything linear at lower duty cycles? That is, will an IC60 at 20% last for three times as many calendar days as an IC20 at 60%?
  2. My automation is a Pentair EasyTouch. Should (or must) my SWG also be from Pentair? If not, is there a recommended brand?
  3. My pool is open year-round, and the water temperature is below 60F for 4-5 months. Will I need to chlorinate with LC during that time?
  4. Is it an easy DIY install? Do I need anything (check valve, etc) other than the cell and controller?
  5. Does it matter (for warranty or other reasons) where I buy the thing?
  6. Any questions I should have asked but didn't?
 
Last edited:
DrewLG said:
I gather that running the cell at 100% shortens its life.
Click to expand...
I asked about this and it’s not true. Whenever the cell is running it’s running at 100%. When you select say 60%, that means that the cell is running that percent of time while the pump is on. So if your pump is on for 10 hours, it’s running for 6 (60%) of those hours at 100%.
DrewLG said:
My automation is a Pentair EasyTouch. Should (or must) my SWG also be from Pentair?
Click to expand...
when I made the switch I stuck with the equipment I already had. Be sure to size your cell for twice the volume, or more, of your pool.
DrewLG said:
Will I need to chlorinate with LC during that time?
Click to expand...
Yes. The SWG will slow down or stop producing at colder temperatures.
DrewLG said:
Does it matter (for warranty or other reasons)
Click to expand...
For the warranty to work out you have to have it professionally installed initially. I’m not sure what the warranty is, if any, if you DIY it.
 
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Kul answered a couple of these but I thought I'd hit all of them for you.

DrewLG said:
I gather that running the cell at 100% shortens its life. But is everything linear at lower duty cycles? That is, will an IC60 at 20% last for three times as many calendar days as an IC20 at 60%?
Click to expand...
As kul said, it is a time based percentage. For Pentair cells it is a 5 minute cycle. So 100% means it is on for the full 5 minutes. 20% means it is on for 1 minute and off for 4.

DrewLG said:
My automation is a Pentair EasyTouch. Should (or must) my SWG also be from Pentair? If not, is there a recommended brand?
Click to expand...
I would keep the same brand as your automation. This would allow you to control the SWCG through your EasyTouch. If that is not important to you, I know there are a lot of folks on here who like Circupool for a stand alone unit.

DrewLG said:
My pool is open year-round, and the water temperature is below 60F for 4-5 months. Will I need to chlorinate with LC during that time?
Click to expand...
Possibly. The literature for the Pentair cells says it shuts off below 52F, IIRC. The salt readings can go wonky at lower temperatures which can cause the salt level to read lower (or higher but that's never my case) and cause the cell to stop producing because of low salt levels.

DrewLG said:
Is it an easy DIY install? Do I need anything (check valve, etc) other than the cell and controller?
Click to expand...
If you are comfortable doing PVC plumbing, and light electrical work, it is an easy DIY install. What parts you need may depend on where you are installing in your circuit. You may also consider installing a heater bypass at the same time (assuming you have a heater and it does not already have one).

DrewLG said:
Does it matter (for warranty or other reasons) where I buy the thing?
Click to expand...
I don't know all the ins and outs on the warranty coverage. As kul mentioned it has to be professionally installed, but I THINK that is as simple as just needing a 'professional' be that someone with a handyman business, plumber, electrician, etc. so that you have a receipt from a valid business that provides the services needed for a proper installation. I would reach out direct to Pentair for any questions about the warranty.

DrewLG said:
Any questions I should have asked but didn't?
Click to expand...
You could ask @newdude for his dissertation on the subject, as well as his handy dandy cost calculator that really should make the decision to go with it a slam dunk.

--Jeff
 
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Turbo1Ton said:
You could ask @newdude for his dissertation on the subject, as well as his handy dandy cost calculator that really should make the decision to go with it a slam dunk.
Click to expand...
Small pools don't see the overwhelming cost savings, because 1 gallon of 10% makes 12 FC for DrewLG. With a DIY install, the first cell would be a wash. With a pro install, it would would take 2 or 3 cells to wash the install costs, but still ultimately wash.

An IC20 will produce about 350 jugs worth for him and the IC40 has better ROI but at 5X may have electronic failure before the plates are depleted.

However. Not sourcing / lugging / adding jugs is still always worth any upfront costs.

Also, while needing to add LC in cold water is true, it's overblown IMO. UV demand is peanuts by then, if anything at all. So your LC dose might last weeks. It's a small effort for a huge gain 8+ months a year.
 
newdude said:
Also, while needing to add LC in cold water is true, it's overblown IMO. UV demand is peanuts by then, if anything at all. So your LC dose might last weeks. It's a small effort for a huge gain 8+ months a year.
Click to expand...
Great point, that I forgot to make. I only have to add LC once a week or less in the winter when my SWCG is not producing.

--Jeff
 
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newdude said:
Small pools don't see the overwhelming cost savings, because 1 gallon of 10% makes 12 FC for DrewLG.
Click to expand...

The cost to chlorinate my pool is so low that I wouldn't really notice whether the SWG was half as expensive or twice as expensive. Cost-saving isn't the reason I'm considering it.

But I don't understand this. An IC20 produces the same total mass of chlorine gas regardless of pool size. And that mass is equivalent to 350 gallons of 10% LC, which costs the same whether you're going to pour it into a big pool or a small one. So how does a big pool save more money per cell than a small pool?

newdude said:
However. Not sourcing / lugging / adding jugs is still always worth any upfront costs.
Click to expand...

It's not much trouble for me to trade in 4 empty LC jugs for 4 full ones 8 or 9 times a year. But yeah, it isn't nothing. And Liquid Feeder maintenance only takes a couple minutes every few months, but if I had to explain it to someone it would definitely sound like more trouble than it's worth.

So convenience is really the main reason I'd switch. But I'd still like to know how that small-vs-big ROI thing works.
 
DrewLG said:
But I don't understand this. An IC20 produces the same total mass of chlorine gas regardless of pool size. And that mass is equivalent to 350 gallons of 10% LC, which costs the same whether you're going to pour it into a big pool or a small one. So how does a big pool save more money per cell than a small pool
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Becsue the rest of us can upsize further to 40k or 60k units at much cheaper than the sizing would suggest. So for a little more money, my cell makes triple (1000 jugs worth), which would cost well over $6k at Walmart. The $1800 larger cell and even possibly $1800 to install it are dwarfed by the $6k+ in bleach.

For you to upsize so the ROI is there, the cell would be so large in proportion to the pool that the electronics would fail before the cell was depleted.

Marty has an IC40 on a 6k pool. His great grandson may inherit it one day. :ROFLMAO:
 
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newdude said:
Becsue the rest of us can upsize further to 40k or 60k units at much cheaper than the sizing would suggest.
Click to expand...

Ah, that explains it. Thanks.

newdude said:
For you to upsize so the ROI is there, the cell would be so large in proportion to the pool that the electronics would fail before the cell was depleted.
Click to expand...

Hmm. A 10000-hour IC20 will produce enough chlorine for 7 or 8 years here. Should I be concerned that the electronics will fail in that time? Are the SWG electronics particularly fragile? And are we talking about electronics in the cylindrical SWG itself, or in the control box / power supply at the other end of its cable?
 
DrewLG said:
A 10000-hour IC20 will produce enough chlorine for 7 or 8 years here. Should I be concerned that the electronics will fail in that time?
Click to expand...
No that's totally in the reasonable window. An IC40 would be in the 16 year range and that's a bit crazy for an outdoor electronic. It's not impossible but I wouldn't bet on it either. Lol.
DrewLG said:
Are the SWG electronics particularly fragile?
Click to expand...
No. But one thunderstorm or power surge is all it takes and 5 years of cell life is gone. Or a bad seal that allows water in.
DrewLG said:
And are we talking about electronics in the cylindrical SWG itself, or in the control box / power supply at the other end of its cable?
Click to expand...
They are independent and either could go. But if the controller went, you could replace just that and not lose the cell too.
 
Thanks, I've ordered an IC20 and the crazy-expensive transformer that goes with it.

FYI, although many other products do require "professional installation" for maximum warranty coverage, it looks like the salt cell is covered for its 2-year maximum even if I install it myself: Pool Product Warranty Information

I have another question:

The installation instructions say that the cell needs 12-18" of straight pipe in front of it, presumably for the flow switch, and that it should be located at least three feet away from the heater outlet. The straight pipe (below the cell in my vertical installation) is no problem, but the simplest installation will put the cell right on the edge of three feet away from the heater. What's that heater-to-cell distance for, and how important is it for the distance to be > 3 feet?
 

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DrewLG said:
The installation instructions say that the cell needs 12-18" of straight pipe in front of it, presumably for the flow switch, and that it should be located at least three feet away from the heater outlet. The straight pipe (below the cell in my vertical installation) is no problem, but the simplest installation will put the cell right on the edge of three feet away from the heater. What's that heater-to-cell distance for, and how important is it for the distance to be > 3 feet?
Click to expand...

Heck, congratulations... You read the manual. That's 5 steps ahead of most PB's, it seems. Mine installed my IC40 no more than 20" away. Came out, made a 90, hit a check valve, then another 90, then turned right into the IC40. Definitely no straight pipe in front of it. I ran like that for at least 6 months with no issues, before I reworked some things, got rid of the UV lamp, added an intelliPh, and added a heater bypass.


IC40 Install.JPG


If you are close to 3' away, I would say that is way better than probably most installations out there.

--Jeff
 
kul said:
DrewLG said:
  1. I gather that running the cell at 100% shortens its life. But is everything linear at lower duty cycles? That is, will an IC60 at 20% last for three times as many calendar days as an IC20 at 60%?
Click to expand...

I asked about this and it’s not true. Whenever the cell is running it’s running at 100%. When you select say 60%, that means that the cell is running that percent of time while the pump is on. So if your pump is on for 10 hours, it’s running for 6 (60%) of those hours at 100%.
Click to expand...
Just to close the loop on this and provide a broader view for future viewers...From @JoyfulNoise :

"My comment and assertion is based on my experience (many years worth) in electrochemistry. You are assuming a very idealized process where the plates wear down uniformly. I can tell you from direct experience that they don’t. You are also assuming that pool water is a good medium to generate chlorine from. It is not at all. Chlorine generators for pools operate far from ideal conditions and so the more stress you put on the plates by running them at a 100% duty cycle, the worse off the catalytic coating is going to fare.

There are two main factors that affect the electrolysis of chlorine gas - current density distribution across the plate and cell AND mineralization of the plate surface. In a bipolar electrolysis cell, the current “crowds” mainly at the edges of the plate and at any “hot spots” on the surface. Current crowding is a problem in any electrolytic setup. What it typically does is causes the catalytic coating to degrade along edges first and anywhere there are hot spots. At these high current density areas you also get greater precipitation of minerals, mainly calcium, from pool water. The calcium mineralization is non-conductive for the most part so it also exacerbates the irregular current distribution.

To abate some of these problems, cells are designed with a three electrodes where the outer plates are often ground and the center plate is charged. The plates are also set into non-conductive dividers to help keep the current from flowing around the edges where the electric fields are the least uniform. One then does periodic current reversal to alternate which side of the plates are anodes and which are cathodes. This helps to more evenly distribute the inherent damage across all plates as well as reduces the amount of scale formed on any one side. The plate spacing and voltages used are set to minimize as much current variation as possible but there will always be current bulge due to a flowing electrolyte.

My admonition is this - the more you can let a cell “rest” by keeping the output % low, the more chance you give for mineralization to be redissolved into solution. The more you drive the plate with no OFF time, the more those plates sit in a high pH, highly oxidative solution. That chemistry can not only cause the precipitation of scale but also the dissolution of ruthenium metal from the plate. The Pourbaix diagrams for the stability of ruthenium species in chloride solutions gets very complex with multiple different soluble species being possible. Ruthenium is a weird metal in that some of its oxides are insoluble while other oxides can actually exist as a gas phase. Ruthenium hydroxides and chlorides are very soluble in water. It’s complex behavior is what gives rise to its usefulness as a catalyst."

Source: Running a SWG at 100% and Cell Life
 
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