Higher chlorine loss than last year

[chem geek]

If the pool has high levels of chlorine and/or exposure to sunlight, the CCs can stay near zero. It all depends on the nature of the organics in the pool. Some only slowly form CCs so sunlight can break it down as fast as it is produced. Others such as ammonia from chloramines very, very quickly and will register on the tests before they get broken down.

As recommended, I would shock the pool and also brush the sides. Though maybe you don't actually have algae, odds are you've got something that needs to be broken down and more likely than not it is algae trying to form. A slimy feel is probably an algal slime layer getting formed. Either that or your pool is oozing something it's alive, it's alive!

Richard

[dancu]

Brought it up to 20.5 ppm, pump is running
I will test and brush in the morning
Thank you again, you guys are great!

[dancu]

In the morning FC 20.5 8am s
Last night 9.5 7 pm
This morning 8.5 7am lost 1ppm overnight
Good enough or do I have to bring it back up to 20ppm ? ,slime is gone...

[chem geek]

Personally, I'd play it safe and keep it at shock level another 24 hours. A 1 ppm drop overnight is not huge going from 9.5, but it may indicate something is still getting killed or broken down even if it's not visible. Better safe than sorry.

[dancu]

Didn't play it safe and now I am sorry...3.5ppm at 5.30pm....
Back to shock level tonight...seems like an a large drop compared to overnight
even with the added uv.

[dancu]

6/24 pm 3.5 ppm, added bleach to 25ppm(9 jugs supposed to be 18.9 ppm,did I test to soon at 2 hrs?)
6/25 am 23.5ppm
6/25 pm 13ppm, added bleach to 25 ppm(4 jugs are supposed to be 8.4ppm but I tested a 12 ppm increase after 2hrs)
6/26 am 24 ppm
6/26 pm 12 ppm
6/27 am 11.5ppm
6/27 pm 5.5ppm
losing 6 ppm during the day, yes it was hot and sunny but I am in northern new jersey.....Any suggestions to bring this down?

[chem geek]

Other than using a cover, I'm not sure what to suggest. You are already at 60 ppm CYA. A 6 ppm loss out of 11.5 ppm is about half and given that you only lost 0.5 ppm at night it would appear that this loss is due to sunlight. This is the peak time of year and even in northern latitudes the amount of solar radiation is quite high. The difference in northern latitudes is that this situation doesn't last very long.

I used to think that operating at a lower CYA level would save you chlorine. So running at 30 ppm CYA you would go from 7 to 3.5 ppm FC and only use 3.5 per day which is less. But now we have reports and experiments (in this thread) of CYA saving more chlorine even at the proportionately higher CYA levels. So that would say going to 80 ppm CYA or higher might help (the effect is non-linear) even maintaining the higher FC level. So I'm stumped and until we get a lot more data on true CYA protection of chlorine, I don't know what to say.