I have been maintaining my FC between 4 and 7
(20K gallons, CYA 50)
I add bleach at night after testing and shoot to raise to somewhere between 6 and 7 and have been steady seeing that FC has maintained nicely, not dropping below 4 even on sunny days.
My question is, are most here using the FAS/DPD test to test their chlorine when they test.
The other test (called the OTO, right?) simply tests a range of chlorine levels and I wouldn't be very confident trusting it to really tell me a FC level - so, I use the FAS/DPD every time - pretty much daily!
Is this a total waste or is this the way most do it around here?