Well shit man, where do I begin? Lol
Couple of them:
I use an 2" abs coupler for drain. It would be hard for me to describe how tall the half up in the tube ends up. Anyways, Drilled tight, but with a little epoxy underneath. Keep in mind, this is 6" ROUND. Problems with Drains on square tubes don't exist. Than 2" abs pipe for riser and to reservoir,
1/2" pipe up on the inside. The tweeks would be how big the holes were and where aimed at.
Gph per certain length of tube. Ended up with around 400 gph per 8.5' - 9.' length of tube/rail.
There's allot more
None of them THAT special. But I sure did dial in them tubes. Toot toot! Lol