Need help with location for drain Holes

[twobytwo]

I'm planning to drill my 120g tank... I've built up the courage to do it myself. The bottom is Tempered... so I'm going through the back. I'm drilling 2 drains (Herbie) and drilling a hole for return. Most herbie articles Im reading all go through the process of bottom drilling.

from: http://gmacreef.com/herbie-overflow-...method-basics/
"Help the Siphon get going on it's own "” by having the height of your main valve standpipe about 6″ deeper than the operating water level of the overflow, usually the height of the emergency standpipe."

For side/back drilling, that doesn't sound right to have the main drain 6" lower than the water level & emergency drain... but maybe it is right and I'm just being cautious about it for no reason. So, for side/back drilling should there still be 6" from water level/emergency drain to the main drain? Should the main drain and emergency at the same height on a back/side drilled tank? If not the same height, what should be the difference? I'd like the water level to be as high as possible. How close to the top of the glass can I drill to get the highest water level?

Also the return line hole - should it be at the same height as the main drain or emergency?

Should I just use a screen/strainer on the wet side of the drain, should I be using a box around the drains? On the wet side, Should I be using a 90 degree elbow, as I've read some articles using, or is that only necessary when drilling the bottom?

Ideally, with side/rear drains, would the main drain bulkhead be completely submerged as indicated in the article (which uses bottom drilled)? I understand the emergency drain would be at the water level. If the main drain is completely submerged... does it matter how high (or deep) it is at all?

 

[twobytwo]

Bump... any help? Just need to know if all my holes for bulkheads to my sump (main drain, emergency, return) are supposed to be at the same height? Thanks

 

[jinks]

I might be misunderstanding what your asking but i will take a shot at it.

All the drains are drilled at the same level. The return should be closer to the top so that you can put a siphon break in it. Dont put it so close that it makes the glass weak but still up there. How high up you put the drain will depend on if you have a overflow box and how big it is. If you are just going to put it in the tank then when the pump is turned off you will drain water down to the drains level. I tried this on a tank and it was a pain.

 

[JMorris271]

Just so the holes are no closer to the edge of the tank than the diameter of the bulkhead you are drilling a hole for is good based on what I see,.

 

[Thunderfan]

I have been researching this and I am going with the bean animal style. 3 holes for drain but it makes better sense to me. In that system it looks like the hole height is determined on making the third pipes turned up 90 just below waterline. I will silicone an overflow box to tank to cover elbows after plumbing is done.

 

[Teenreefer15]

look up herbie overflow, you'll get a ton of results.