Why do SWG cells only last 3-5 years? It may be a stupid question but one I've been pondering. I just ordered a replacement after 4 full seasons so it's done it's service.
Donnie

Cells are usually rated in amp-hours so run time has a big effect. But maintaining good chemistry is a big factor as well. Keeping a proper CSI balance has helped me keep scale off the cell so I don't need to clean the cell very often. Next month will be my 6th year on the same cell but I don't expect it to last too much longer.

I leave my pool open even through cold Oklahoma winters. Water temps at 32 degrees at times. Does that affect my run time or are amp hours added only when it's actually "on"? I never actually calculate CSI but maybe I should.

Donnie

I believe most systems keep from energizing the cell when the water drops below 50F or so.

Amp-hours are only when the cell is on and as carlos pointed out, most cells shut off when the water gets too cold. Mine shuts off below 50 degrees.

Thanks guys. Cell is barely producing chlorine. It has some out put but it's minimal. It's been great since install in December 2006. Looking forward to seeing my amp hours this evening.

Donnie

Low chlorine output can also be a symptom of an algae bloom (i.e. FC is constantly being used up). Have you measured the salt level and compared it to the SWG reading? Also, check CC and see if it is a little high.

Thanks. No algae bloom. Water is perfect. Really. I have a small pool and stay on top of things. Thanks to many on this board a few years ago my pool has never been anything short of sparkling (except for the sauted mushroom thing). The SWG has slowly faded and I have had to increase the power from level 1 to level 3 over the last 12 months or so. The cell is clean and from what I've learned lately...it's just reached the end of it's life. I have a salt test kit and calibrated it's reading to the SWG so I'd say it's good +/_ 100 anyway. The pool has been getting full days of sun and 32 days of the last 42 with 100+ temps. As far as CC's go, I have never measured them over .5 or a trace. It's rarely more than the wife and I using the pool and she keeps it clean. I've been able to bring FC up to 3.5 with 48 ounces bleach each evening and the following evening it will be 1.5ish. SWG is on level 3 at 65% and showing 8 amps / 25 volts (or vice versa). CYA is good at 80 Ph stays fairly constant at 7.4-7.5.

Donnie

My point about the SWG salt reading is that a failing cell tends to show low salt when a test kit shows it as being higher. Amps tend to be on the low side as well. If the salt level is reading correctly and your amps level is where it normally is, then it might not be a failing cell.

Also, the chlorine extinction increases significantly with higher water temperatures. I always need to turn up the SWG during the heat of the summer even though I have a solar cover on to block UV.

I'll test the salt tonight also. I haven't done a drop test on it lately. It was reading ok on the SWG at 3100. Water temps have been bad. As high as 94 in the afternoon and a refreshing 85 in the mornings. Thanks for the info. I'll post back tomorrow!

Donnie

Wow. Keep in mind I purchased this unit brand new. 21703 amp hours (yes, checked 3x). Level 3 @65%, 24v 8A. Salt 3100 on SWG, 3000 drop test. FC 2 (added 48oz bleach) CC 0 as usual. Ph 7.6 (added 3oz muratic acid). 92 degrees!!!! Maybe the amp hours wasn't zero upon installation? I do run the pump anywhere from 12 to 18 hours a day (we like the fountain noise). Anyway....just did the math. 21703 hours is 904 days and with a 12 hour run time I guess I got my moneys worth out of it! I think we'll learn to live without the fountain noise a little more. If I cut my run times back I bet I can get 8+ years out of the next cell. Wadda U think?

Donnie

You can't just reduce the run time without reducing the FC residual. You need to add so much chlorine per day to make up for what is lost and the amp-hours is proportional to the chlorine production. So unless you reduce your FC residual, you can't reduce the chlorine output and thus you cannot reduce amp-hours.

I have had periods of high FC. Usually in cooler weather. I have just been a "set it and forget it" guy and that's probably not the best avenue. I think with my new cell I will monitor my FC a little more frequently. I got to the point where if it looked good it had to be good. I really do appreciate your feedback.

Donnie

the catalytic coating on cells wears out with use

Thank you. Thats the answer I was looking for. Not that I didn't enjoy and learn from other replys!

Donnie

With cell life not so long and expensive it would be nice if someone figured out a way to rebuild them for half the price.

well...
it's not worth it

majority of the cost is in the plates as the coating has precious metals in it (ruthenium oxide or iridium oxide)

non-self cleaning cells can be reconditioned, as half of the plates are just bare titanium, so you can just replace the anode.
however with self cleaning ones you have to replace all the plates which only leaves the cap and connectors that can be salvaged.

also not all cells last 3 years and not all of them are expensive

And not all last only 3 years. It really comes down to Hours of Operation (rather than years of operation). For example, a seasonal pool will have twice the cell life as a pool opened all year long. During the off season, when the pool is shut down, you're not using any hours of operation.
As the cell generates chlorine, as Strannik said, you're wearing off some of the precious metal coating.

Replaced my cell and all seems well except for the 16V 5A reading. Is the 16V okay? Water chemistry is as close to perfect as it can be.

Donnie