Does the chlorine / CYA chart minimum FC mean that at no point in the day should it drop below that?

[WeAllSwam]

When I chlorinate my pool to the target (around 8ppm) overnight, it lowers to about 3.5ppm by the end of the next day (it's 105 degrees with summer UV in Texas right now). So, it gets below the minimum of 5ppm (for 60 CYA) before I re-chlorinate. Is that going to cause a problem?

Note: I did fail the overnight chlorine test, so that explains part of why chlorine is disappearing so quickly. I'm going to create a separate thread for that issue, but for now I wanted to know if the minimum is a hard limit.

 

[Texas Splash]

Is that going to cause a problem?

It can. Unless you had a large pool party or something, you should be concerned if you lose more than 4 ppm in a 24 hr period. In cases like this, I would first do an Overnight Chlorine Loss Test to ensure you don't have a large organic demand eating your chlorine. If you pass the OCLT, increase the CYA a bit more by about 5 to 10 ppm. When I used liquid chlorine, I kept my CYA between 60-70 due to the intense heat.

 

[Holydoc]

You should never drop below the minimum recommended value for FC. You can keep from doing that by setting a higher target FC. You are safe to swim in your pool up to SLAM level which is FC=24. So do not be afraid to raise your daily target FC.

Doh! I see Texas Splash just posted before me. I totally agree with his suggestion to perform an OCLT just to make sure you do not have any algae starting.

 

[Newdude]

Minimum is lava. I like to take pictures from afar. Some people like to run up and get selfies. Guess which one of us calls EMS on behalf of the other ?

 

[WeAllSwam]

Thanks for the feedback. I was afraid of that I let normal people standards of acceptable ppm level influence me.

I'll say my Hail Marys and shoot higher so it doesn't drop below the minimum.

 

[Newdude]

I'll say my Hail Marys and shoot higher so it doesn't drop below the minimum.

When you aim above target for FC, it's more Dirty Harry than Sister Margaret.




I know what you're thinking algae, did he raise the FC to 3, or 10............. Do you feel lucky, punk ?