Water is clear but appears to be consuming considerable chlorine


Gold Supporter
LifeTime Supporter
Nov 29, 2015
Carrollton tx
I replaced the SWG a few weeks back and it was running at about 60 % for about 8 hours a day
Tests show about 2 ppm chlorine
We had some small swimmers yesterday so I retested and added 1 gal bleach and upped the SWG to boost at 100% and added 2 pucks to help raise my CYA
Also added 40 lbs of salt to raise NA from 2900 to 3100
And finally added 16 oz acid to bring PH down to 7.4

The water stays between crystal clear and really clear most of the time
But after adding the gallon of bleach and the 2 pucks to a floater and the 100% boost I expected the PPM to be above 5 today

I have to assume the chlorine is being consumed by something

Leaving for about 2 weeks in about 4 days so looking to get the pool as close to perfect as I can
I have a gallon and a half of bleach left

Im predicting a recommendation to post a full series of tests and to slam


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Not sure I am convinced you need to SLAM Process. Yeah, a full list of tests would help. You don’t say what your CYA was or your CC is. You know you had low CYA.

Low CYA + long days of sunlight + low salt so low SWG performance could all add up to a FC deficit. Sounds like you are addressing these issues. I would test and monitor and see the results of your changes.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
Your prediction of the test results is spot on. Like ajw22, let's see what your results are before you SLAM.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

Just for reference, your SWCG at 100% should increase you FC by 2.4 ppm in 8 hours. At 60% it is only 1.4 ppm.

Most pool use 2 to 4 ppm of FC per day and the lower your CYA the more you will use. In the middle of a Texas summer you need to either run longer or increase your normal SWCG output.

You need to run an Overnight Chlorine Loss Test or OCLT... Here is how.. Overnight Chlorine Loss Test

What CYA level are you running?

When algae starts it is not necessarily visible... By the time you can see it, it is too late..


Jim R.


Gold Supporter
LifeTime Supporter
Nov 29, 2015
Carrollton tx
Cya was 55 about a month ago and the salt and cya in this pool both decrease over time due to leak / rain/ auto fill

cc is almost always zero - once in a great while it will be .5 or 1 - Ive seen CC maybe 2 or 3 times in the 3 years ive owned the pool

I'll check cya tomorrow

Thanks to all for chiming in


Bronze Supporter
Apr 6, 2018
I have a Jandy TruClear which produces .93 lb I think a day and I have to run it 11-12 hours a day at 80% to keep my chlorine up. Of course I am in Texas with full sun all day and 100+ weather so that might have something to do with it.


Gold Supporter
TFP Guide
Jun 7, 2017
Damascus, MD
This happened to me this month as well. I was using more chlorine than usual/expected and my testing showed my CYA had dropped to 50ish. I added 4lbs of CYA last night to get it back to 70ish and will monitor chlorine usage expecting it to rise and usage to wane. I also noted my salt was lowish at 3000 (K-1766). The SWG reports 3400 (within the error margin of +-400) so I added more salt as well.