I hope this helps. This design is for my dwarf seahorses. My goal with this was to slow the flow down. The only openings from the PVC bottom tube are to the smaller PVC tubes pointing up into the tank. The
Plastic tubing, connected to the smaller PVC's are the only part that are going to have actual hole punched in them. The rest of the pipes and tubing will be sealed off. My hope is that this will created a "fountain" effect, causing the released water to buffer the surface water, with out blowing the little ponies all over.