Overnight FC loss question

[graffster]

Hi Expert Pool People!!

I'm still 'battling' my pool, (though I know with the help of this sight, I WILL WIN!!!)

Two quick questions about shocking: (And I looked for these answers in Pool School, but didn't find them.)

1- In the CYA/CL chart, there is a difference in a SWG and non-SWG (the smaller chart for the SWG). DO I read that the Shock Level is the same for both types of pools??? (I know in some of the responses that I've recieved in previous posts, it seemed as if they were interchangable.)

2- For the Overnight FC test, the morning test is to be performed "before the sunlight" hits the pool. It's probably just a matter of semantics, but does that mean before the sun actually comes up or before you can see the "sun beams" in the pool? (Seems like a silly question, I know...)

Time to go test again...and brush...(My baracuda's diaphragm split, so he's out of commission for a couple of days...) must brush even MORE thoroughly!!!!

Thanks in advance...I know you'll get me on the right track!!!

Kathy

 

[JohnT]

1- In the CYA/CL chart, there is a difference in a SWG and non-SWG (the smaller chart for the SWG). DO I read that the Shock Level is the same for both types of pools??? (I know in some of the responses that I've recieved in previous posts, it seemed as if they were interchangable.)

Yes, they are the same. A SWCG needs the higher CYA to make it easier for it to keep up with the chlorine demand, but it can operate at lower FC levels because of a continuous shocking effect in the cell itself.

2- For the Overnight FC test, the morning test is to be performed "before the sunlight" hits the pool. It's probably just a matter of semantics, but does that mean before the sun actually comes up or before you can see the "sun beams" in the pool? (Seems like a silly question, I know...)

Any sunlight is going to start depleting the chlorine level, but I doubt the first hour or so of daylight is very hard on it. But to be sure, test it early or you'll doubt the accuracy if it shows a loss.