As long as things are moving around it shouldnt be a problem. But you could also run into the problem where there is alot of current and it will blow it right past the filters inlet. I guess the only solution to that would be having a sponge over the power heads inlet, but thats just one more thing you would have to rinse out.
LMAO I don't know why that was so funny but i just cracked up imagining that.
I am setting up a system of PVC in my gravel powered by two power heads to keep everything out of the gravel. The designer of my system never had to vacuum his gravel. A user here gave me the link he has Jay and Silent Bob as his avatar.
Very interesting, I'll try to do something similar.
As for undergravel jet systems, I've read people talking about it on cichlid forums - the general consensus is that it is not a good idea. I probably won't do it.
I will try to get multiple powerheads (hydro koralias) and try to postion them to pump water through the rock structure.
Sump + FX5 + 2217 + 3-4 Koralia, I just need a better idea on placement. Your sand looks great btw, very clean!