Black Pool Water

[pminct]

I understand replacing the sand in the filter - no problem.

How much/how often do you think I will need to shock to get rid of residual Baquacil?

How early should I start this if I want my pool open and swimable by Memorial Day, even though it will be much too cold for me to swim (but not too cold for kids to have their annual Memorial Day swim!!!)?

Patty in CT

[waterbear]

You need to raise your free chlorine to 15 ppm (or slightly higher) and KEEP IT THERE by testing at least 2 times a day (more will be better) untill your free chlorine is holding overnight. Your chlorine will not hold until all the biguanide is oxidized.