Going to the BBB

[aylad]

Not sure, but I would think it's probably the metals in the water reacting with the sudden high chlorine "pocket". Does the cloudiness clear up fairly quickly? What's your pH? With metals in the water, you're going to have to be careful to keep the pH and chlorine on the low side...

Janet

[CarlD]

It will help if you post your current levels of
FC
CC
TC
pH
T/A
CYA
CH
Plus any metal level test results you may have.