SWG Pool Is Crystal Clear But Chlorine Is Zero

by Liz
(Alpharetta, GA)

I have a 20000 gallons vinyl pool. For the past two weeks I notice that my chlorine is not reading zero and I keep shocking the pool thinking that the burning sun is causing the evaporation. Then I got it tested in a pool supply store last June 23 and I got the following readings:

FAC - 0
Calcium Hardness-170
Copper, Iron, Phosphates -0
Temp -85

I then did a superchlorinate mode last June 24 and the next day the pool was crystal clear. So I was thinking it must have worked but still the chlorine is zero.

I have a compu pool system that I was using since 2012 and I noticed that it keeps on testing the salt. I told that to the tech and she said it might be the control is not communicating properly with the chlorine generator. But I can see bubbles at the side so I believe my chlorinator is working. So before I change my lcd screen is there any other things that I might still be testing?

Hi Liz. There are a couple of things you can do. First is to try to recalibrate the cell. You can go to the owner's manual for that, or try these links if they're right for your cell:



It can take up to 24 hours for the re-calibration process to take effect and catch up.

Also be sure your system is not throwing any codes. They sometimes change so it's more difficult to keep up on the newer codes. With the exception of the FC, all of your readings are good. When was the last time it was cleaned out?

Let's keep in mind that a chlorine cell's efficiency lasts about 3 - 5 years. After that they start to diminish.

I would start with the re-calibration then go from there.


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