need help with overflow (pictures to explain)

[das75]

Want to place a 20g refugium above and to the side of my sump. Got a 20g, drilled a hole on the side for a 1" bulkhead, put in a coast to coast (horizontal) overflow on the side and thought to test before cutting into my plumbing.

Problem I have is the flow seems limited with the 1" bulkhead installed sideways to about 300gph.

My preference for splashing is I drain into the sump below the water level but if the discharge is submerged or even a short vertical stub I get pumping such as in this video pumping.

If I don't have a vertical pipe at the end of the horizontal run, just the elbow, the tank backs up. Don't have room inside the tank so tried a 1" Tee's for venting a few different ways on the outside (directly off the bulkhead, next to the elbow on the left, Tee turned sideways etc) and at 300gph the water floods the overflow then the whole tank level goes above the weir.

Can't believe I would loose 50% of the capacity of the bulkhead if sideways, what am I missing?

First picture is how I want to install, discharge either into the skimmer section or last baffle. Next picture is first test, no Tee, third is one configuration with a Tee.

 

[das75]

sort of a bump on this.

 

[t-bone2]

i would get rid of that little sump arouind the pipe

 

[Mattmcf]

why not slow down the flow into the fuge? you do not need to move alot of water trhrough it for it to work.

 

[Playa-1]

Instead of pushing all the water thru the fuge. Add a tee with a ball valve. allow 25% of the water thru the fuge and allow the rest to continue on to the sump. The ball valve will allow you to easily control the flow through the sump for fine tuning.

 

[das75]

To explain the purposed layout (first picture) the ref is going to be feed by the upper return. I'm going to Tee into the 2" run (blue line) and control the flow by ball valve on the remaining downward leg into the sump.

The refugium will flow back into the sump (red line) either into the skimmer compartment or last baffle area through the 1" bulkhead and 1" pipe (though the red line in the picture happens to go through the valve it is not connected to the outflow of the ref).

Each of my drains run about 500gph so not planning on running all through the sump, again will be allowing some (probably half) so only 250 gph through the ref. If the valve becomes blocked it means ~500gph into the ref.

The issue I have is why the max flow the 1" horizontal bulkhead and 1" pipe runs can only handle a max of 300gph (either straight or vented)?

 

[Roy G. Biv]

I use this on the inside of the tank. It is on a 90 degree elbow. This way I can twist it clockwise or counter clockwise to adjust the height of the water in the fuge.

 

[Roy G. Biv]

Also on this pic.. I would put a T where the elbow is to allow air to suck in or escape at the drop. Water level will rise a bit in the tank to push the air bubbles down. You will get UP/DOWN/UP/DOWN in the tank as the air collects at that elbow.

 

[LobsterOfJustice]

If you think about it, it makes sense for the flow to diminish. It is because you have such a long horizontal run before the vertical drop. It is acting like your overflow is actually where your pipe bends to vertical, and the long run of overflow pipe is acting as an overflow box would. Before being "cleared", the water has to find its way into that pipe and meander its way to the vertical portion. Gravity isn't working with you here.

 

[Playa-1]

I still think you got way too much flow thru the fuge.
Good luck with that.