Overflow on a 125gallon

[SJReffer408]

I have a 125 gallon that im drilling for overflows to my sump (40 breeder). Is 2 holes ok (1" holes) and 2 (3/4) return holes . Or do I really need the 3rd hole ? I bought a internal overflow box from Amazon that handles 1800 gph . are the 2 holes suitable for the internal overflow box. I was just going to put 90's down the back of the tank/bulkheads, and no 90's inside the internal overflow box. Is this ok or should I be drilling a 3rd hole????? :hammer:

 

[fishgate]

If you want Bean, you need a 3d hole. 2 will still allow full-siphon but without as much safety margin. It is better to go with 90's down-turned in the internal box. This will prevent a whirlpool starting and LOTS of noise with that.

I have the exact setup as you and I went with an internal/external box setup. 2 1" holes from internal to external, then 3 1" holes in the bottom of the external box to the sump. Set up as modified bean. Dead silent and LOTS of flow. Out flowed my DC6000 so I just upgraded to a DC9000.

 

[mcgyvr]

3 x 1" bulkheads for the overflow..
1 full siphon w/valve to adjust flow
1 open channel
1 emergency
http://www.beananimal.com/projects/silent-and-fail-safe-aquarium-overflow-system.aspx

 

[KAMIKAZE0214]

I have a 125 gallon that im drilling for overflows to my sump (40 breeder). Is 2 holes ok (1" holes) and 2 (3/4) return holes . Or do I really need the 3rd hole ? I bought a internal overflow box from Amazon that handles 1800 gph . are the 2 holes suitable for the internal overflow box. I was just going to put 90's down the back of the tank/bulkheads, and no 90's inside the internal overflow box. Is this ok or should I be drilling a 3rd hole????? :hammer:

I would drill a 3rd hole for bean animal. It really works awesome

 

[uncleof6]

Internal/external overflow designs are a step backwards functionally. Generally the internal boxes are too small, equating roughly to nothing more than corner overflows, which defeats the whole purpose of making mentioned modifications for higher performance. I designed one of the earliest internal/external "bean systems," if not the first, and current concepts are a step down from what I found to be more trouble than it is really worth.