Yeah, the ribbed PVC also looks ribbed on the inside, and it being flexible would take out a 90 or so, but I can see the ribs slowing the water down a bit.. I think I'll go with the regular PVC. I'll post a pic of my new design idea in a sec too. And also, what exactly would a drip pan need to look like? Like just. A piece of plexiglas with a buncha holes? I just need something to go over my bioballs to spread the water over all the bioballs instead of just on the edge where the water overflows into.