CircuPool SJ-40 Issues - Can't "see" it working anymore?


Well-known member
May 15, 2016
Tulsa, ok
I purchased a circupool sj-40 last year. All last year, I could easily see that the unit was working by looking at the salt cell. It would bubble or put off a slight haze and I knew it was working.

This year, nothing. I cant seem to keep FC in my pool and the water passing through the powered up SJ40 is clear and stays clear. My salt level is at 4000ppm and I've tested this numerous times.

All the self diagnosis and lights are green on the unit. Thoughts?


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
The cell cycles on and off depending on the % you have set. If I recall correctly the SJ cells have a 2 hour cycle. So if you have 50% set it will run for 1 hour out of two, off for one hour, then reverse polarity and run one hour, etc.

What % output do you have set? How long do you run your pump?

Good chance you are walking by looking at the cell during the idle times.

How about posting a set of test results. What is your water temp?

Have you done an Overnight Chlorine Loss Test with the SWG off and on?


Well-known member
May 15, 2016
Tulsa, ok
I've set it to 100% and Full Blast and turn it off and on and havent seen it put off chlorine at all this year. Last year, I could always see that it was working after I put power to all the equipment.

I'll do a full water test and post.

My salt is 4000 ppm, water temp is 84F. I run the pump 24/7 at one speed or another. The SWCG runs about 18 hours a day at 50 or 75% depending on bio load and season.


Well-known member
May 15, 2016
Tulsa, ok
Yes - I've been adding Atwood pool shock to keep Chlorine in the pool.

I'm using the Taylor K-1766 for salt testing.


Well-known member
May 15, 2016
Tulsa, ok
Hi Guys. Easter got me side tracked this afternoon so I didnt have time to do water testing until now. Here's the results:

FC: 2.5
CC: 0
CH: 200
TA: 100-120ish
Ph: 7.6
CYA: ~60 ish (its cloudy and I cant see very well)
NaCl: 4000
Water Temp: 84F

Lights on the SJ-40 are all green to 100%. Polarity light is green at position 1. Power and Caution light are both unlit.

Edit: After testing, I added 38oz of 31.45% Muriatic Acid to bring Ph into spec.
Last edited:


TFP Expert
LifeTime Supporter
Jan 4, 2016
Sydney, NSW, Australia
You could try disconnecting the cell lead under the control module and reconnecting it, just to rule out a loose connection.

There is also a reset (fuse) button on the bottom where the connectors go in. That might also be worth a try.


Active member
Mar 15, 2016
Fort Mill/SC
I have the same device and I was having the same problem. Then I noticed my power light was flashing. This can mean a few things, one is the flow is too slow. I increased the rpm to try and make sure i was getting the required 30 gpm, which I felt I was well above. What I discovered, was I had to power cycle the device before it would recheck the flow and start producing chlorine. So if you power on your SWG BEFORE your pump gets to the required speed, your out of luck unless you cut the power. I had mine on a timer and it was just coming on right before the pump, now i have it come on right after, and I was able to lower my speed considerably. Maybe its the same issue or similar.

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