FC from 6 to 0.6 in 48 hours?

[dkode]

This may be a remedial question but this is my first FC pool. Old pool was SWG and I didn’t maintain myself.
If you look at my testing logs here: PoolMath Logs

it feels like I’m adding an excessive amount of chlorine to the pool every other day. Usually anywhere between 32-64 oz. even then, when I test the following day, or miss a day, it drops from 5/6 to 0. Should I be concerned?Do I not have the fc high enough?

im in Austin TX and then UV is starting to get pretty high during the day. Does the FC loss occur in higher temps or higher UV?

thanks

 

[JoyfulNoise]

2-4ppm FC loss per day is normal. On the high side that would require 48 fl oz of 12.5% liquid chlorine every day. Higher UV and heat in the summer accelerates chlorine loss. You shoild do an overnight chlorine loss test to see if your pool might be growing anything since the FC has fallen well below your minimum value for sanitation. If you pass the OCLT than you can try increasing your CYA to 60 or 70ppm to help reduce UV losses.

Installing an SWG or a Stenner Chemical pump would probably improve your consistency in keeping the FC at the correct levels.

 

[dkode]

Thanks for the info. What does an overnight chlorine test entail? I added chlorine late tonight (9pm). I suppose I test it again in the morning prior to the sun hitting it?

 

[wireform]

Bring the water up to slam level as per poolmath, check it half hour later and replenish any chlorine it may have lost and then check it once more say 15 minutes later. In the morning before the sun hits the pool and check the FC and see how much it dropped from the last reading the night before. More then a 1 ppm drop means you have something growing and will need to keep the pool at slam level till it holds the chlorine. All this while the pump runs 24/7 and no SWCG in the meantime.