Sump Rock

[ctmedman]

I have bioballs in my sump that I would like to get rid of and replace with another mechanism of biological filtration. Some have recommended that I fill the sump up with rubble rock but I was wondering if there are cheaper alternatives. Maybe lava rock?

TIA

 

[Guest]

anything you can get your hands on IMO. I would use cheap dry base rock rubbled up with a hammer. Add some live rubble rock and then some rock from your display and whammo. Few months it will be loaded with pods and bacteria.