Hi everyone, am just curious, i intend to add charcoal to a pail of water for changing water, in this pail i will bubble it for a few days before adding to the tank, of course the water will be conditioned, as i found out from a bro that charcoal can absorb harmful chemicals, does anyone does this? also when you age water, do you cover it with a lid to reduce the rate of evaporation, and if you don't cover, wll the water turn bad like nitrates increasing or some other things like that?

thanks
Jason