Pool Filled! Quick question

[AnnaK]

Since you have results for FC and TC you can calculate CC.

Total Chlorine (TCl) = Free Chlorine (FC) + Combined Chlorine (CC)
or
TCl - FC = CC

I know ChemGeek will faint at this simplistic explanation but CC represents the FC that's bound up with organics and is not available to do any sanitizing work.

If your test and the subsequent calculation produce a CC of 1 ppm or more you may have an algae bloom starting even though your water is still clear. That's when it's time to shock the pool. However, as long as you stay on top of your water treatment with daily pH and Cl testing and add bleach as required you may never have to shock. I've had my pool for 5 years and haven't shocked it but once after a lengthy absence during which the pool was unattended.

You'll get the hang of all this soon enough.

[CarlD]

Anna's got it pretty much right.

I think TCL must be TC, so subtract FC from it to get CC.

FAS-DPD is simplyh the best form of chlorine testing that's available to home or professional users. It can measure FC and CC up to 100ppm and is very accurate. It is not to be confused with DPD chorine testing, which can bleach clear at too high FC levels and make you think you have NO chlorine.

FAS-DPD is a powder you mix into a little bit of pool water, which then goes pink/red. You then add drops of a reagent, counting drops until the fluid goes from colored to clear--each drop represents .5 or .2 ppm of chlorine (depending on which amount of water you use). You then add another reagent that picks up CC, and use the first till it's clear the same way. If there's just a tinge of pink and the first reagent clears it with just one drop, I'm not really worried...but if it takes more, Anna's right--something's cooking.

[dmarsh70]

Thanks guys!! I think I got it now.. .maybe