Autopilot digital nano

Dustballs

Well-known member
Nov 25, 2014
79
Ft. Lauderdale, FL
Hello everyone, after comparing the ideal water balance per the owners manual and the sticky there appears to be a few inconsistencies (cya being one).

Just want to confirm with the experts that I should follow the sticky vs owners manual.

Also didn't see anywhere in the manual that speaks to the water temperature and the effects on the SWG. Can you enlighten me?

Thanks as always.


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JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
Yes, follow our guidelines, not what it says in the manual.

At colder water temperatures the SWG stops working very well. Fortunately, there is far less need for chlorine at cold temperatures. Autopilot units will keep working, all be it slowly, at low water temperatures, but most people simply turn them off.
 

pwrstrk

TFP Expert
LifeTime Supporter
Aug 17, 2012
4,758
Elverson Pa.
Couple of reasons we recommend a higher CYA level for SWG's
You get better protection for FC burn off from the sun and it also helps with PH levels rising with less runtime of the SWG with the higher CYA protecting your FC. Your SWG contributes to PH level increase.
Some SWG stop making chlorine when water temps get into the low 50's. Why, I don't have that answer. 😎
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
The reason that SWGs stop making chlorine when the temperature drops is that water conductivity is a function of temperature and drops roughly 2% per degree Celsius. So at 50ºF compared to 80ºF that's 0.98^(30*(5/9)) = 0.71 so a roughly 30% drop in conductivity due to the higher resistance. It's not just that the output is lower (for the same applied voltage) but that different reactions can occur instead of just producing chlorine. Such reactions produce oxygen gas or chlorate and these reactions are not the ones designed for the highly optimized coatings on the electrolytic plates. This was described in this post. For some systems, they don't separately measure the temperature so they just see lower temperature as if the salt level was lower and stop for that reason because lower salt levels will produce more oxygen gas instead of chlorine and again this isn't good for the coatings.
 

Dustballs

Well-known member
Nov 25, 2014
79
Ft. Lauderdale, FL
Thanks guys. I usually run my pump for 8 hours a day. Is that the typical SWG run time? I'm guessing once my FC drops below 10 I can adjust to make sure FC is stable.


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JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
8 hours is a bit longer than it is usually necessary to run the pump, though that varies from pool to pool. Smaller SWGs on larger pools require more pump run time than the other way around. The pool it's self typically only needs four to six hours.
 

Griswald

Well-known member
Jul 7, 2014
690
Hope Mills, NC
My pump runs 12 hours, but my SWCG is set to 20%.

Personally, I like the water to be circulating a lot, I know it's not necessary, but we get a lot of air-borne pollens in my neck of the woods. They make an unsightly mess.
 

boston62

LifeTime Supporter
Jun 7, 2014
476
Fort Myers, Florida
Griswald is that a single speed pump, or you running that on a slow speed? I had to cut back on my run time, because it was raising the FC to high with Autopilot set at 20%. I cut back to 6 hrs. 1 @ 2750 rpm 5 @ 1200 rpm..doesn't it raise the FC?