Question for the beananimal overflow experts

[Werbo]

Thanks guys. In summary:

1. Main drain fully submerged with a strainer 3-4 inches below the secondary drain.
2. Secondary drain has a T fitting followed by a down turned elbow to set the height of the overflow box (2 inches below the water level of the main tank). Airline tubing (as in picture) coming out the top.
3. Emergency drain with a T fitting and an upturned elbow (to allow stop water from flowwing when your arm is in the tank). Cap the emergency drain to make it air tight?

[Cal_stir]

Originally Posted by ScubaSteve

1. Fully submerge the full siphon otherwise you get horrible sucking sounds. At the sump, don't submerge the end more than a couple inches otherwise you won't get the siphon started.

2. Yes, the secondary drain sets the level (sort of). The main siphon handles most of the flow, so with somefine tuning IT sets the level of water in the overflow (if the flow in = flow out, there is no change in water level) but if set this way it's easy to cause fluctuations. Decrease the flow through the main siphon with a gate valve until water JUST starts to trickle into the secondary over flow (thus the secondary effectively sets the height of water in the overflow box). If you have the bulkheads on the bottom of your overflow box (ie. you have risers coming up vertically from the bulkheads), I would set the secondary overflow a little bit higher than the entrance to the main siphon. This gives you a bit of leeway if you cause a fluctuation (like sticking your arm or a bag of frags in the tank) before the water level in the overflow box gets down to the main siphon and makes horrible sucking sounds.

3. I have my emergency drain and a straight pipe coming up from the bulkhead below (no elbows or anything). The end of the emergency is about 2" higher than the entrance of the secondary (so about 1" higher than the middle of the T I use for the secondary) and is about 1" higher than the operating height of the water. Again, this gives some leeway in terms of fluctuations so the system doesn't flip out if you stick your arm in the tank.

4. The main siphon is closed (as in no air can enter the pipe), so nothing special there. I'd add a strainer if you don't have teeth on your over flow (I had a cleaner shrimp who used to ride that water slide continuously until he took one ride too many). Secondary and emergency pipes... I wouldn't bother putting strainers on them. There's little to no flow through them to actually suck up critters (though they could crawl in) and they are basically your "Oh S***" buttons, so my thinking is to have as little restriction on them as possible. Just my opinion, others may differ.

In terms of special piping on the secondary, you just need an air tight cap on the end of the pipe with a hole drilled to fit a piece of airline tubing into. The tubing is bent over and set just above the water line in the overflow. If the water rises to plug the end of it it will cause the secondary to become a full siphon and it will literally drain your overflow like flushing a toilet (Very cool to watch... errr, the overflow, no the toilet).

Unfortunately, this is the only pick I have handy of my overflow. If you need more, let me know.

yours is an external box so you don't need elbows and your box is a bit deeper than most internal overflows.
you want to set the system up so small amount of water is flowing thru the sec drain, as much as you can without it gurgling, that sets the height of the water in the box(that and where you put the bulkheads)

[Cal_stir]

Originally Posted by Tyler Werbowski

Thanks guys. In summary:

1. Main drain fully submerged with a strainer 3-4 inches below the secondary drain.
2. Secondary drain has a T fitting followed by a down turned elbow to set the height of the overflow box (2 inches below the water level of the main tank). Airline tubing (as in picture) coming out the top.
3. Emergency drain with a T fitting and an upturned elbow (to allow stop water from flowwing when your arm is in the tank). Cap the emergency drain to make it air tight?

do you have an internal or external overflow?

[ScubaSteve]

Originally Posted by Cal_stir

do you have an internal or external overflow?

He has a 42x12Hx5W external overflow (on the 1st page).

[ScubaSteve]

Originally Posted by Tyler Werbowski

Thanks guys. In summary:

1. Main drain fully submerged with a strainer 3-4 inches below the secondary drain.
2. Secondary drain has a T fitting followed by a down turned elbow to set the height of the overflow box (2 inches below the water level of the main tank). Airline tubing (as in picture) coming out the top.
3. Emergency drain with a T fitting and an upturned elbow (to allow stop water from flowwing when your arm is in the tank). Cap the emergency drain to make it air tight?

1. No need for 3-4". 1" will suffice. I'd say 2" tops.

2. Correct, though it doesn't have to be 2" below. To low and it splashes; too close to the top and you might have issues with overflowing the box if the water level changes suddenly (again, arm...). Mine is 2.75"-ish below the surface doing 600 gph on a 12" wide overflow. No splashing.

3. Emergency drain: don't cap it to make it air tight and no need for a T or elbow. Just run a pipe straight up and have it a bit above the normal water level.

[Cal_stir]

Originally Posted by ScubaSteve

He has a 42x12Hx5W external overflow (on the 1st page).

DOH! my bad

[Werbo]

This is great info. Thanks again.

Could you provide a picture or link to an example of a strainer used on the full siphion drain

[scubadawg]

I noticed that you have caps on 2 of your overflow tubes, is that necessary?

[Cal_stir]

the caps are for cleaning out the pipes if nec