55 gallon substrate question

[pacu_keeper]

I have a 55 gallon barebottom tank housing a 6-7" pacu (yes I know hes going to outgrow it....very soon) but I was wondering what would be a good substrate for his tank.I was thinking about sand but dont know if it will interfere with my filter (penguin 350 biowheel....crappy filter) or how easy it would be to keep clean. Im open to suggestions.

 

[cornbread_5]

but a cover over the in take and it shouls be fine

 

[wannaarro]

Also don't fit the intake tube too far down if the fish stirs up the sand, and always turn off filter when doing a gravelvac/waterchange. I've got sand in all but my planted tank, and the various filters (esp. HOB's) have done fine.