How long did your cell last?

[PJM361]

We had a pool installed back in 2012 with a Hayward Aqua Rite SWCG. I bought the T-15 cell under the advice that a more powerful cell working at 50% would last longer. It's rated for a 40,000 gallon and the pool is only about 17-18,000 gallons. So ather only 3 seasons it's not working. I confirmed this by calling Hayward and they had me run through the diagnostics on the control panel. So my question is what brand & model do/did you have and how long did it last? Also if you went with a different brand cell to replace it, what name, model and how much longer or shorter did it last?
Thanks

[mas985]

Hayward/Goldline T-15 Cell, just shy of 10 years. I wouldn't buy anything else.

But pool water chemistry and maintenance of the cell is critical to a long cell life. Most often it is poor chemistry and aggressive cell cleaning that shortens the life of the cell.

Did you find a lot of scale on your cell when you inspected it?

Did you frequently have to use acid to clean the cell?

Did you track CSI as part of your chemistry management?

What were the symptoms of the failing cell?

[PJM361]

Very little scale, the reason I called Hayward was because the check cell light kept coming on and my salt level reading was 2000ppm when I opened the pool this year. After adding a bag of salt the # went down to 1900 then hours later went slowly up to 2700 , but still would only run with limited output (low salt flashing) then added another bag and the # actually went down to 1700. I was having problems at the end of last season with fluctuating numbers. So I did the acid wash. What is CSI?

[mas985]

You didn't answer this question: Did you frequently use acid to clean the cell?

Have you replaced the cell and did the problem go away?

CSI is calcium saturation index. It is a very good measure of the probability that calcium will come out of solution and scale things. The best way to determine CSI is to use the pool calculator: poolcalculator.com

For the longest life of the cell, target between -0.5 and -0.25.

[PJM361]

I cleaned with acid just once. I haven't replaced the cell yet. The reason for my polling is to find out if the cheaper replacements last as long as the OEM haywards. Don't know if I did the calculations right, but it said I have a csi of -1.24. I have a vinyl lined pool and my CH is at 40, FC 3.6, PH 7.2, TA 100, temp 72* I didnt use CYA last year because it was clogging up my filter which in turn would restrict flow and shut down my SWCG at low rpm (800-1000). I have an automatic safety cover that is always closed unless someone is in the pool or I'm cleaning it so I don't really need it. I don't have a problem with high PH, accually just the opposite usually have to add borax. But once I get the levels up it usually only needs a little once in a while.

[mas985]

I didnt use CYA last year because it was clogging up my filter which in turn would restrict flow and shut down my SWCG at low rpm (800-1000). I have an automatic safety cover that is always closed unless someone is in the pool or I'm cleaning it so I don't really need it.

But you do! Using chlorine without CYA can be very corrosive which could explain why your cell failed. Even indoor pools should have a small amount of CYA to prevent this.

But even with a cover, you sometimes remove it during the day don't you? FC will not last even a few hours without CYA so you risk not only algae but bacteria breakouts. Plus, given the pool is exposed to sunlight on occasion, CYA will allow you to reduce the output of the SWG so it will last that much longer. Also, CYA should not clog your filter, that must have been something else, probably algae from the lack of FC. If added to the pool correctly, a sock in front of the return, there should be no problem with CYA.

Honestly, I think the problem with the short SWG life has more to do with the way you are managing your pool.

[JimK]

My last T-15 cell lasted 7 years.

[PJM361]

Sorry I haven't gotten back sooner, but good news is the cell is working again. My FC went over 4 even though the light was flashing and supposedly it was working at a reduced rate. I finally went down to the local Leslies and had my salt level tested. They said 2100 while my aquarite said 2400ppm. So I added more salt. I've added at least 160lbs so far this past 10 days. I don't drain my pool for the winter and I didn't backwash the filter at the end of the season. I opened it up and cleaned it manually. So how am I losing so much salt without a leak? I know evaporation lowers the water level, but the amount of salt is suppose to stay the same except for when the water is splashed out. Also mas985 can you give me a link to the chlorine without CYA is corrosive info because the hayward tech I talked to this morning said it wasn't. He said it would just help keep the FC level up, but not effect the cell. When I did add CYA 2 years ago it was flakes and I just poured it around the pool like I did with the salt. I can't recall if it just got sucked in through the bottom drain or I vacuumed it up, but I remember seeing it clogged up in the strainer of the pump. At that moment I realized why you need to put it in a sock. �� What I meant by clogging of the filter was I would have to increase the RPMs on the pump to 1400 or more because the no flow light would come on and the auto prime wouldn't work so I had to switch the pump to 3 minute prime. I also found out from a hayward tech that I was putting too much DE in the filter after backwashing. He said only put in 75% since backwashing doesn't remove all of it. One weird thing that happen today was while looking at the instant salienty # I flipped the switch on or off and the salt level went to 0. I then turned it on again and the # went up to 700, then I did it again and it went up to 1500, then 2100, 2400, 2700 and finally to 2900. It's finally back to work and the PH & TA are right on target.

[mas985]

Just google: https://www.google.com/search?source...69i57.1071j0j9

Chlorine is a strong oxidizer and if not buffered by CYA it can cause issues. Chem Geek had posted about this on several occasions. A quick search revealed this:

It is well known that high chlorine levels (especially in indoor pools without CYA) are corrosive to metals and that high chloride levels accelerate stainless steel corrosion (see this post).
Those are known mechanisms with the only issue being the rate of such corrosion in 3000 ppm salt pools. It has been proposed that stray currents may also be to blame, but no clear mechanism for that has yet been found and that would not explain corrosion of the metal parts in a pool cleaner, for example, since there is no current flow from the electrolysis in the salt cell possible in that case -- the metal is just exposed to salty, chlorinated water and is not electrically connected (and such corrosion in non-SWG pools is still in salty, chlorinated water, but with lower levels of salt). If the bonding wire and all metal components were to have a positive voltage applied to them, then there is no question that metal corrosion would be greatly accelerated.

http://www.troublefreepool.com/threa...ll=1#post14022

Here: http://www.poolforum.com/pf2/showthr...-to-salt-pools

There are probably a few more in here: https://www.google.com/search?num=50....0.kC-aNC4-XGM

As for your decreasing salt level, it is either a leak or splash out. You have to be losing water (other than evaporation) for the salt level to decrease.


If your readings are changing a lot or the cell sometimes works or sometimes doesn't, it could be the solder joint issue:

http://nocellpower.blogspot.com/

[PJM361]

Sorry I haven't come back sooner, just found this going through my old emails. I found out after my last post that the lost of salt was happening because of a leak in the main drain . So I shut that side of the return lines and I'm just using the skimmers. Thanks Mark for the links I'll try to read them all when I have time.