Bean animal help/questions

[Alucard]

Just built a new setup 40g dt with 40g sump. Overflow is modular marine 800gph with 1/2 bulk heads which lead to 3/4 pvc down to sump and exits 3/4" below water line. I got everything dialed in and it works great, absolutely silent but every once in a while the main drain line with completely empty the overflow box then let it fill back up and go back to normal. Any ideas or should i be worried? thanks

 

[Reefing Madness]

 

[ReeferBob]

You need a little bit more flow in your open channel. Crank closed your full siphon a little.

 

[Blitzie]

Do you have a gate valve on the main drain?
The idea of a full siphon drain aka Bean or Herbie is you dial the gate valve so water just slightly fllows down the secondary line. This will prevent the siphon you are getting from the primary

 

[West1]

3/4 pvc for the drains? I was under the impression that 500gph was max for herbie or bean overflow. Or is it just the overflow gph but you are actually pushing less gph through?
Can you post a picture? I'm in the middle of a herbie overflow with two .75 bulkheads and 3/4 pvc, I was going to redrill and install 1" bulkheads for my fluval sp2 (guessing I will get 800-850 gph).

 

[ReeferBob]

3/4 pvc for the drains? I was under the impression that 500gph was max for herbie or bean overflow. Or is it just the overflow gph but you are actually pushing less gph through?
Can you post a picture? I'm in the middle of a herbie overflow with two .75 bulkheads and 3/4 pvc, I was going to redrill and install 1" bulkheads for my fluval sp2 (guessing I will get 800-850 gph).

3/4 will get you around 1300 gph with a full siphon. Is your tank pre-drilled? If so, usually they temper the glass after they drill it meaning you cannot re-drill. Make sure before you attempt! And even if not tempered, not sure I would re-drill.

 

[West1]

3/4 will get you around 1300 gph with a full siphon. Is your tank pre-drilled? If so, usually they temper the glass after they drill it meaning you cannot re-drill. Make sure before you attempt! And even if not tempered, not sure I would re-drill.

The Biocube is drilled and both 3/4 bulkheads are already in. No leakage so far. 1" PVC to 3/4 bulkhead