Seriously though Marc is 100% right about being careful with this stuff. It can kill your tank, make sure that your drip/feed line can't hit the sludge. The pH controller and float switch are superb ideas as well.
For those of you who are new to this . . .
CaO or CaOH make a solution with a pH of about 11.0 or 12.0. It doesnt take a whole lot of pH 11.0 liquid to run a typical system well up into the 9.0 range or higher. If the sludge gets in the tank and hits anything it will burn it, not heat burn, pH burn(although there is a lot of heat generated when you mix it up) . . . if you dont believe me put some CaO or CaOH on your arm and drip a little water on it.
DO NOT REALLY DO THAT!!!!!! sooner or later it will happen by accident and you'll know what I mean.