FC consumed, but no CC

[SniperFire]

Hello all - seeking guidance on chlorine levels

Just opened my pool - 38k gallon, solid cover, water clear without green tint, 51 degrees on average, CYA @ 30ppm

Dropped in liquid chlorine to get to ~4ppm at noon yesterday; ended up at 1.8ppm FC and 0.2ppm CC at sun down; then 0.2ppm FC and 0.2ppm CC at dawn.

Question #1 - if the pool was “dirty” shouldn’t CC increase as FC is consumed? Otherwise, should I be assuming that the FC is getting consumed by the sun?

Feel free to blast away at my understanding - I know it’s limited!

 

[noturbizniss]

if i recall correctly, cc only goes up when it doesn't break down. You will always see FC fluctuating but want CC to be 0

 

[SniperFire]

Definitely agree that CC should be zero. More trying to confirm if consumed FC creates (if only temporarily) CC. If it does, then I can infer that when FC is being consumed and CC increases that the FC is creating CC and the pool should be getting cleaner. That said, if the FC is consumed and the CC is constant and low, that the pool is effectively already clean and that the FC is evaporating into the air vs reacting with contaminants.

In this application, 0.2CC tells me that my pool is a little dirty, but i’m trying to figure out where “the rest” of the FC is going - if that makes sense at all

 

[mknauss]

Trying to correlate CC to how clean your pool is will not work. CC's are quite volatile.

FC does not evaporate into the air. It is either consumed by UV or organics.

 

[SniperFire]

Thanks - helpful.

So practically speaking, as long as FC level drops in darkness, regardless of CC level, I need to keep adding chlorine?

 

[mknauss]

You will need to add chlorine every day to maintain your FC in the target level range.

If you lose more than 1 ppm FC over night, called a Overnight Chlorine Loss Test, you need to SLAM Process.