Question about overflow in 90 gal build

[recess62]

In the process of a 90 gal build. The tank has 2 drilled corner bulkheads in the bottom. One bulk head is 1 inch. The other is 1.5 inches. Which one should I use as the main and which one should be the emergency overflow? I was going to use the larger as the emergency. Is this correct? If not then why

Thanks

 

[recess62]

Anyone?

 

[kschweer]

I'm not to familiar with herbie type drains. Maybe the [HASHTAG]#reefsquad[/HASHTAG] can help out.

 

[Sabellafella]

In the process of a 90 gal build. The tank has 2 drilled corner bulkheads in the bottom. One bulk head is 1 inch. The other is 1.5 inches. Which one should I use as the main and which one should be the emergency overflow? I was going to use the larger as the emergency. Is this correct? If not then why

Thanks

I think it depends on how much flow youll be putting through the tank. I think the bigger drain is for emergency.

 

[wpeterson]

The official answer is that your emergency drain in a Herbie setup should always be equal or larger size than your siphon drain - so if the siphon drain fails completely, your emergency drain can take it's capacity.

So officially, you should use the 1" as main/siphon drain and 1.5" as an emergency standpipe 6" above the level of the siphon inlet.

Realistically, however - you will likely be running the 1.5" drain restricted enough that a 1" drain fully open may work as well. I had a 1" and 3/4" drains in my 90 and ran the 1" as the siphon drain. It's your decision, but following the official route is always safest.