I only have the 90's on the ends of my returns because they have a big lip that helps my berlin sock stay on. Also I have done lots of research on ABS and I believe it is a myth that it is harmful when using it for an aquarium set-up. ABS is used in lots of applications I never used it for a full set up because I find that it does not seal as well as PVC. Not to turn this tank journal into a discussion about ABS, but not to worry my return only hastwo 90's of ABS. Thanks for the headsup on ABS.
