Blocking Light in Sump?

[MKLKT]

Originally Posted by intarsiabox

How long is your photoperiod for the refugium lights? How about phosphate levels? The refugium shouldn't be causing the algae problems and I think you should look at other causes before blacking out sump compartments.

I'm inclined to agree, the lamp I have in my sump is a basic Can Tire shop light that isn't exactly spot focused and it bleeds light into the rest of the sump while on (12hrs) and I don't have any appreciable growth of anything other than the macro algae. The clear vinyl tubing has a bit of coralline algae but that's about it. Work on stopping what's feeding the nuisance algae and it'll go a lot further for your tank's health.