At what temp does SWCG become ineffective?

[jmattdoss4]

I'm trying to decide when to close our pool. I understand that waiting until water temp goes below 60 is recommended. However, I think I remember reading somewhere that the SWCG does not work properly below a certain temp. Can anyone help me out with that temp?
Thanks,
Matt

 

[Melt In The Sun]

It's somewhere around 50-60, but you can always check your unit if you're wondering...the display should say "COLD" if it has shut off.

 

[timerguy]

We installed ours in March and our water temp was 56-- the owners manual said 50 but it didn't generate until the temp was closer to 60.

 

[pooladdict]

You should get a. Warning when water is to cold, just supplement with bleach til you close.

 

[mas985]

Technically, the SWG doesn't become ineffective at any temperature, but most SWGs will shut off below a certain temperature. This is because of software not physics. It would continue to generate chlorine if allowed to albeit at reduced rates. So the bottom line is run it until it shuts off on it's own which for Goldline, should be 50 F.

 

[Mike_k]

Technically, the SWG doesn't become ineffective at any temperature, but most SWGs will shut off below a certain temperature. This is because of software not physics. It would continue to generate chlorine if allowed to albeit at reduced rates. So the bottom line is run it until it shuts off on it's own which for Goldline, should be 50 F.

Isn't it true that the colder the water, the higher concentration of salt is required? I might just be imagining this...

 

[mas985]

The production rate of an SWG is proportional to the amps delivered to the plates which in turn is proportional to both temperature and salt level of the water (i.e. conductivity). But as I pointed out before, it is software that stops the unit from producing CL at low temperatures and/or low salt levels. But if the software was bypassed, the SWG would continue to produce chlorine just at a reduced rate.

So if you are trying to compensate production for low water temperatures, you could increase the salt level to get back to the same production rate as the higher water temperature.

 

[timerguy]

Curious, how do you bypass the software?

 

[mas985]

You don't. That was a hypothetical.

 

[jmattdoss4]

Thanks everyone!

 

[Poolsean]

There is additional wear on the Ruthenium Oxide coating when operated under cold water temperatures. The tendency for cold water conditions is for the power supply to try and push more power to the cell. IN most cases, the power supply will shut down under cold water protection. AutoPilot will go through an Automatic Temperature Compensation adjustment, in which the output % setting will decrease as it gets colder, and when it drops to 55 degrees or colder, it will go to 1%. BOOST will override it for 24 hrs of production.
Adding salt to the upper range of the manufacturers acceptable salt range, will help compensate for the cold temps, before shutting down.

 

[cwescapexlt4x4]

This poses something for me to think about being in Phoenix, we do get cool and don't plan to "shut down" the pool as the dog(s) will use the pool I am sure but maybe I will have to add salt to compensate. Thanks for the great advise as usual.

 

[mas985]

Normally, you really shouldn't need to compensate for lower water temperatures because of a couple reasons.

1) UV extinction tends to go down with lower sun elevations in the sky during the winter so less FC is used up during the daytime hours.

2) Algae grows much slower at lower water temperatures so maintaining a lower FC level is usually fine.

I find that during the winter, I can actually turn DOWN my SWG by quite a bit (~25-50%) and still maintain the same FC level as I did during the summer.

But, if you find you do need higher FC, you can just turn up the SWG instead of adding more salt. Adding salt should be a last resort because you don't want it too high come next spring.