Not maintaining chlorine

[mgtfp]

That means you are producing 9h x 0.267ppm/h = 2.4ppm per day.

Or with PoolMath:



Without a cover, that certainly wouldn't be enough. Never used a cover, but it should help some. It dropped 4.5ppm in 4 days, or a bit more than 1ppm per day, so your pool needs about 3.5ppm per day. Without cover, that wouldn't be unusual this time of the year.

I would suggest to do another OCLT without cover. If you pass that again, then do an OCLT with cover. It be might be that chlorine is oxidizing something in/on the cover.

 

[8ightiesfan]

Here's some humour for you today. My test results using my Clear Choice Labs test kit vs the pool shop test. I won't include the chlorine result as I had only just added chlorine and took a water sample 10 minutes later so result is not reliable.

My test
TA 60
pH 7.6
CH 375
CYA 80
Salt 4600

Pool shop
TA 80
pH 7.8
CH 250
CYA 130
Salt 4200

 

[8ightiesfan]

That means you are producing 9h x 0.267ppm/h = 2.4ppm per day.

Or with PoolMath:

View attachment 466647

Without a cover, that certainly wouldn't be enough. Never used a cover, but it should help some. It dropped 4.5ppm in 4 days, or a bit more than 1ppm per day, so your pool needs about 3.5ppm per day. Without cover, that wouldn't be unusual this time of the year.

I would suggest to do another OCLT without cover. If you pass that again, then do an OCLT with cover. It be might be that chlorine is oxidizing something in/on the cover.

Thanks mgtfp, I will try the OCLT with the cover on/off.

 

[Youfah Mizzum]

80s,
I am having similar struggles.
My SWG also running at near 100% but getting CL loss despite very clean water. I'm about 5 hours north of you so just a tad warmer. I did a OCLT and found I was getting lower reading in the morning so I'm currently SLAMing.
Like you, I am suspecting the filter media/sand but mine is only 2 years (new pool as at Nov 2020) so I find it hard to believe that's the cause but I ran out of options.
I even got my SWG replaced under warranty in case that was to blame.

How are you testing your water? (Edit - never mind, I see you have a CCL kit).

 

[8ightiesfan]

80s,
I am having similar struggles.
My SWG also running at near 100% but getting CL loss despite very clean water. I'm about 5 hours north of you so just a tad warmer. I did a OCLT and found I was getting lower reading in the morning so I'm currently SLAMing.
Like you, I am suspecting the filter media/sand but mine is only 2 years (new pool as at Nov 2020) so I find it hard to believe that's the cause but I ran out of options.
I even got my SWG replaced under warranty in case that was to blame.

How are you testing your water? (Edit - never mind, I see you have a CCL kit).

Good to know I am not alone, I have not done another OCLT yet, I don't think that is my issue here the pool is as clear as ever, like crystal clear, and I passed an OCLT without the cover.

I have just raised my salt to aim at 5000ppm after speaking with the manufacturer of my chlorinator who were really helpful. I will monitor at 5000ppm salt to see if that helps, if not I will be moving on to a deep clean of the sand filter as the next step.