Can't keep chlorine up

Carolyn · May 18, 2015

Hi - I'm back after receiving my TF-100 test kit - big improvement. But we are continuing to have problems with getting the chlorine level up & keeping it there.

Background: Jandy Salt Water Generator - Water crystal clear - weather for the last few weeks has been cloudy with lots and lots of rain. Like everyday. Pool was shocked several times since opening, but haven't SLAM'd (we've just come over from the dark side

) We are able to get chlorine level up using bleach, but by the next day, it's low to zero again. Not much sun at all lately. Running the pool filter 8 hours a day, Polaris 2 hours a day (very little detritus in pool).

Test results performed today:
Salt - 3200
Chlorine Drop Test - zero chlorine
Calcium hardness - 108 ppm
TA - 90
CYA - 80
Chlorine = 0
pH - 7.5 - 7.8 (I'm finding it hard to match the colors exactly)
Bromine - 0

This is all new to me, and I'm trying to figure out if the problem is that the SWG is not working, or if some of the chemistry in the pool is off or what else could be going on. I went out just now to see if there if the service light was on or if there were any error codes. It said chlorine production was set to zero, though I know I had set it to 80%. But we've had several thunder storms since then - could lightning have changed it?

Any help at all would be appreciated to avoid a service call.

Azgirl71 · May 18, 2015

If there were power outages or power surges that probably could have reset the SWG. I would set it back to 80% and test again later.
What is your CC?

tim5055 · May 18, 2015

What test kit are you using to get the numbers??

We do not advocate "shocking" our pools, we follow the SLAM Process (that you are aware of) when there is a problem.

With 0 chlorine I would manually chlorinate with liquid to get up to at least 10 and as you have reported cloudy water do a Overnight FC Loss Test (OCLT) tonight. This will show if something has started to grow in the water with the lower chlorine levels.

Continue to manually chlorinate as you sort out the SWG issues, or if you fail the OCLT SLAM the pool with the SWG turned off.

Donldson · May 18, 2015

Congrats on the kit, as you are seeing it is very nice to have!

If your FC is dropping to zero over a single day then you have something in the water reacting to it. You will want to SLAM it to get all of that out. After successfully completing the SLAM your SWG should have no issue keeping up. It is a good idea to shut down the SWG during the SLAM to save cell life and get more accurate FC loss readings. As for whether it is working, I will let others with more experience in that department chime in.

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Carolyn · May 18, 2015

The CC level is .5

We don't have cloudy water - the water is crystal clear. Should I still do the OCLT test? There's practically no leaves or other detritus in the pool.

Azgirl71 · May 18, 2015

I would do a OLCT just to be sure.

tim5055 · May 18, 2015

Carolyn said:
The CC level is .5

We don't have cloudy water - the water is crystal clear. Should I still do the OCLT test? There's practically no leaves or other detritus in the pool.

Wow, I have to slow down my reading.... I apologize, I saw the cloudy and missed it was the weather :taped:

The way you listed the tests confused me, but now that I look at it I understand.

In the Tf100 there are 2 chlorine tests, the FAS-DPD test (the one with the powder) and the OTO test (the one with the yellow drops). You generally only need to do one of them. What most people do to conserve chemicals is test once or twice a week with the FAS-DPD and the other days use the OTO. The FAS-DPD is very exact as you count the drops, the OTO has a little wiggle room, thus it's not so exact. As your CYA is 80 and the chlorine level needed for that CYA is a minimum of 4 and a target of 6 you are actually on the borderline of using the OTO test.

I would still recommend manually chlorinating with liquid to get up to around 10. This doesn't need to be exact, but I would like it to be above 6. Then get a good baseline FAS-DPD number tonight. Run the pump and SWG all night and test again in the morning. if the SWG is working the chlorine should go up overnight.

Carolyn · May 19, 2015

tim5055 said:
Wow, I have to slow down my reading.... I apologize, I saw the cloudy and missed it was the weather :taped:

The way you listed the tests confused me, but now that I look at it I understand.

In the Tf100 there are 2 chlorine tests, the FAS-DPD test (the one with the powder) and the OTO test (the one with the yellow drops). You generally only need to do one of them. What most people do to conserve chemicals is test once or twice a week with the FAS-DPD and the other days use the OTO. The FAS-DPD is very exact as you count the drops, the OTO has a little wiggle room, thus it's not so exact. As your CYA is 80 and the chlorine level needed for that CYA is a minimum of 4 and a target of 6 you are actually on the borderline of using the OTO test.

I would still recommend manually chlorinating with liquid to get up to around 10. This doesn't need to be exact, but I would like it to be above 6. Then get a good baseline FAS-DPD number tonight. Run the pump and SWG all night and test again in the morning. if the SWG is working the chlorine should go up overnight.

Thanks!! I will give that a try.