Plumbing sizes and drainage

[The Grizz]

My buddy here in Red Deer has a 300 gal that was drilled out for 1" drains & 1" returns, it was nothing but a major PITA!! I suggested to bushing up to 1.5" right after the bulkheads in the OF & it runs 1000 times better. I have always read that the returns should be smaller then the drains & as you can see by my 300 build all returns are 1" & drains are all 1.5". I have the tank filled right now with fresh water to make sure everything is running correctly & it is all smooth sailing, after a lot of tweaking & tuning.

As for the magic # for downward angle, I think about 2 - 3 degrees is more then enough as you don't want a huge drop on a long run.

To add to Wes's post, when I cut the acrylic out for OF teeth I always cut them 1/4" with 3/8" in between.