SWCG not raising FC levels as expected


Active member
May 5, 2020
Our Intex SWCG for our intex easy set agp is not raising FC levels as expected since we had a lot of rain storms. Does this mean we probably need to take it apart and clean the electrodes? Do we need anything special to do that?

Everything had been good for a while up until the rain storms. The pump show no error codes currently, and is at a good pressure of 8 psi. The pool is clear. we use a clear solar cover when not in use and it does have some funk on it from the trees above and the storms.

The FC is steadily decreasing despite increasing the time for running the pump and swcg. Our FC is currently 4.5 from 8.5/9 a week ago. It thunder-stormed several days and I did a backwash, rinse and waste to get the water level to where it should be (bottom of the blow up ring). I knew my chemicals went out with the water so several days later I tested the salt and it was 2400-2600ppm, the cya was around 50/55, FC was still good around 7.5/8. I’m not sure how long the salt had been down, but I’m guessing within a week and because of the rain and then the draining of excess water. So, a few days ago we added more salt and cya.
Now the salt is at 3600ppm - a tad bit high, FC is decreasing and now 4.5, the cya is up to about 65, ph is down to 7.0 and TA is down to about 65.
The FC has gone from 8 to 6.8 to 4.5 over the last 4 days with no additional drain on the water. The water temp has increased a bit from about 83 to 88 degrees and we have been swimming more. The CC was zero until today, it is registering something lower than .5 - I didn’t do the .2 version of the test because I’m almost out of the reagent. I have been running the swcg 5 hours instead of 3/4 this week, and last night I ran it 6 hrs because the FC was only 4.5 and then we swam all day yesterday...today the FC is still 4.5.

We have some granulated liquid chlorine we can add if needed, but I’m mostly trying to figure out why running the swcg a long time isn’t increasing the FC.



Mod Squad
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
Hey there :). Did you use liquid chlorine to start the pool off so that the cell could *maintain* that level? Also anytime you need a quick increase of chlorine to avoid algae, supplement with liquid chlorine.

Don't clean the cell unless you see calcium buildup....every time you clean the cell it shortens its lifespan.

You may have a low level algae problem....consider performing an OCLT to determine-
Overnight Chlorine Loss Test

How many hours per day on the pump, or % on the cell, are you running? You can increase this for additional chlorine production.



Active member
May 5, 2020
We started with the liquid chlorine at the very beginning but that was over a month ago sometime in May I believe. Then got the swcg going (it’s new). We didn’t have the cya going in the beginning and the swcg was keeping it easily at about 4-4.5 and we stopped using the liquid chlorine altogether at least a month ago. Everything seemed to be going fine and we had gotten the FC, cya, ph and salt all to good levels until the rain issues with over filling the pool :(

I was running the pump 5 hrs with the swcg 3/4 hrs of the 5. When we added the salt I ran it for 8 hrs with 5 having the swcg on too. Then, with the water warming we started using it more in the last 10 days and I was running both for the 5 hrs a night. The. Last night I ran both for 6 hrs hoping to bump the FC a little. But no change, still 4.5.

Could dirt and/or algae on the solar cover be the issue? We haven’t figured a way to clean it yet with laying it in the grass and getting grass all over it. Would we just clean it with some liquid chlorine or bleach? Will that kill the grass?

What about sunscreen, would that be something that eats up the FC a lot?

Is it okay to leave the salt at 3600ppm or is that going to be too high?

Where would we see calcium buildup? Just unscrew the electrodes and pull them out and look at them?

Thank you for all your help!

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
I've been going through something similar. I got a new SWG back in April and am seeing now that the FC is falling a bit more than I'd like. So here's what I did:
1 - Rule out algae. I did an Overnight Chlorine Loss Test and passed with zero FC loss in 7 hours of darkness.
2 - With algae out of the picture, you focus on two main things: Is the FC protected with enough CYA and is the SWG performing properly (run time & % output or defective).

Let's assume your water is algae-free, then you go to the feature of the PoolMath APP to see how much lbs of FC your SWG should produce. If you're not making that much chlorine, you might consider scale, but with a new SWG and the last set of test numbers you posted, I doubt that's it. Could the SWG be defective? Possibly. It's just something you'll have to monitor. Also make sure you have the proper CYA of 70-80. We ge nervous going that high, but it's critical for SWG performance in the middle of summer.

Back to organics. If you fail the Overnight Chlorine Loss Test, then you know what to do - SLAM Process. But it certainly would be good to clean the cover well, especially underneath on the water side. Also remember that with summer comes a much higher FC demand from swimmer's bathing load, UV intensity, higher water temps, etc. All of these place a high demand on the water. But I'd start with the OCLT first, this way you can rule-our (or confirm) excessive organics. If that's all good, then you can focus more clearly on the SWG and its performance.