All right, that stuff sounds good. Those things aren't the only mechanical filtration in my system and recently they've been doing more harm than good.
I can't imagine how I'd get macro algae up in there and have it stay, though that sounds like a really good idea. I've got plenty of LR
rubble I could use.
My only reservation is that one time my tiny yellow clown goby went missing and I found him in that overflow. The sponge was the only thing that saved him from getting washed down to where I'm sure he would have died. I guess we'll have to hope he learned his lesson at least until he gets too big to get sucked in there.
I'll give it a shot this weekend and let you know how it goes. Thanks for the advice.