Running a 55K Gal SWCG at 75% just to maintain a 4.0 CL level in a 17K gal pool

[Skurzban]

last year I barely needed to run my SWCG at 25% for 2 hours per day and this year running it at 75% for 6 hours. So running it 9x as much to maintain the same level of chlorine.

The only difference is that last year I had a solid gray solar cover and now have a clear one to produce more heat. Could that really create that much more demand??

I have SLAMed the pool already to rule out algae.

 

[jark87]

Depends on several other factors. What’s your CYA level? If low, sunlight will deplete your chlorine much faster. You could also try the OCLT to make sure you don’t have algae consuming your chlorine.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

www.troublefreepool.com

 

[Rancho Cost-a-Lotta]

I did some quick calculations. Running 75% for 6 hours should generate 3 ppm of FC daily. That sounds about right for this time of year without a cover.

I'm no expert, but I don't believe the clear solar covers do well in blocking UV light, which degrades chlorine.

 

[jark87]

Sorry - I missed your note about the SLAM.

 

[JoyfulNoise]

More heat + more light = more chlorine consumption.

3ppm/day loss is fairly normal.

 

[Skurzban]

Depends on several other factors. What’s your CYA level? If low, sunlight will deplete your chlorine much faster. You could also try the OCLT to make sure you don’t have algae consuming your chlorine.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

www.troublefreepool.com

Thank you for responding. CYA is 55. And I performed an OCLT and revealed no problems. I performed a SLAM anyway.

 

[Skurzban]

I did some quick calculations. Running 75% for 6 hours should generate 3 ppm of FC daily. That sounds about right for this time of year without a cover.

I'm no expert, but I don't believe the clear solar covers do well in blocking UV light, which degrades chlorine.

Right. The clear solar definitely lets in the UV rays. I was just shocked that the 9x difference in SWCG demand could be due to a cover but I guess zero burn off vs high is the answer. Thank you for responding.

 

[Skurzban]

More heat + more light = more chlorine consumption.

3ppm/day loss is fairly normal.

I suppose you are right. Lots of burn off vs no burn off.

 

[markayash]

Thank you for responding. CYA is 55. And I performed an OCLT and revealed no problems. I performed a SLAM anyway.

I would raise your CYA, mine was around 50 and struggled to keep my FC around 5. Raised it to 80 and FC went to 9 with no other changes

 

[Matt F 1]

Have we cleaned the SWCG lately?

After I cleaned mine, I had to lower it from 40 to 10.


.

 

[djdonte]

Every time my FC readings look like the SWG is not keeping up, the CYA is low. I keep it at 70-80ish but in the summer months I need to add some maybe every other month. Once it gets down to around 50 it wont hold FC as well. A SWG is not super complicated at the actual cell level, in that if its getting current and you have salt, it should be producing FC. I always thought there were "levels" of generating but the percent you set it to just creates start and stop cycles. Either on or off. Just like setting and AC lower doesnt make it run any harder. Additionally I can see the cloud of bubbles coming off mine when it is producing.

 

[Skurzban]

Have we cleaned the SWCG lately?

After I cleaned mine, I had to lower it from 40 to 10.


.

I will check it again, but I have virtually no buildup of any kind on the plates. What little there was I was able to blow off.

 

[MrLeadFoot]

last year I barely needed to run my SWCG at 25% for 2 hours per day and this year running it at 75% for 6 hours. So running it 9x as much to maintain the same level of chlorine.

The only difference is that last year I had a solid gray solar cover and now have a clear one to produce more heat. Could that really create that much more demand??

I have SLAMed the pool already to rule out algae.

Understood about the clear cover allowing sun to burn up FC. That was a question I had about clear covers. I am equally interested in your findings about whether or not the clear cover helped generated more heat. Did it make a difference?