Bean or Glass Holes Overflow? 33G Oceanic Cube

[M@!]

I was thinking 2"?

[M@!]

Originally Posted by M@!

I was thinking 2"?

Any thoughts on the holes 2" from the top?

[M@!]

Alright, I built an overflow box which will help me with my hole placement.

Now I have one more question on the Herbie. To make it a true herbie one of the returns needs to be out of the water as an "emergency pipe." With the placement of my holes just an upturned 90 deg elbow will not be out of the water. Should I run a piece of PVC on top of the 90 to get it above the water for a true emergency drain or just run two gated overflows?

How does this gate valve look?
http://www.amazon.com/King-Brothers-.../dp/B000H5ZTUY