Ok, I need some Herbie help here...
I just got water in my new 110 and I'm having a really hard time getting my Herbie dialed in. The water level in the overflow basically cycles back and forth between sucking air and running over into the backup drain. It'll suck air for maybe 30 seconds, then the water level will slowly rise until it overflows the backup drain for 30 seconds, then goes back down to sucking air. Of course, this also means the water level in the retun section of the sump fluctuates as more or less water is held in the overflow.
I have a 1" main drain and the top of the pipe is about 12" from the bottom of the tank (I have one of those 8" tall high capacity suction screens on top of it). The backup drain is about 14" above the top of the main drain and is about 1" below the level of the overflow teeth. So, that means the water level in the overflow is cycling up and down 14".
I'm running an OceanRunner 6500 return pump which puts out about 1700 gph - I tee'd off about 300 gph for the fuge, the 1" SCWD then probably knocks off another 20-30%, bringing me down to 1000 - 1100 gph or so running through the Herbie. I know I'm not maxing out the drain line because, if I open up the gate valve and turn off the tee to the fuge (to put 100% of the flow up to the DT), the drain handles the flow just fine (just noisy since I lose suction).
So, I figure I must have something set up wrong. What should I try?