I have a 30G tank that gets water from my main sump off a mag 9.5 I just bought today. Water overflows down a 90deg elbow, through a bulkhead, around the corner via 90deg elbow, and then down via 90deg elbow and then many other twists and turns before eventually ending back in the tank.
Interestingly enough, I was able to drain a MAG 12 yesterday. It was making a horrible slurping sound (doh, forgot to do the T on the outside with a hole in it) so I shoved a 1/4" vinyl tube down the hole. That shut it up right quick and everything worked fine overnight.
Today I bought a MAG 9.5 (12 was just too strong) and LO AND BEHOLD the 1" overflow can't handle the flow out. To more permanently solve the noise problems I drilled holes in the elbows on the outside and shoved a 1/4" vinyl tube down each of the 2 holes I drilled. Tried sticking a 1/4" vinyl tube into the elbow inside the tank too to no avail. It's just not handling the flow.
What am I doing wrong? It worked off a mag12 yesterday.