How do you stop the flushing

[gflat65]

I got the frag tank hooked up to the 125 yesterday, finally. It breaks siphon over time, though. I have to run the 'return' with the vlave closed because of another small hydraulic issue I have. I have the frag tank draining into my fuge. The connection between the sump and the fuge is not as big as it needs to be, so my fuge is filling faster than it can drain. Easy fix-jst put a bigger connection between them.

However, the overflow is just a bulkhead with an elbow. I used a 3/4" bulkhead and a 1" elbow (1" elbows everywhere on the drain side). It flushes, then fills, then flushes. Is there anything I can do to stop the flushing effect? I have about 1.25" of height to work with, so a durso is not an option.

 

[crumbletop]

Could you put a 90 degree elbow on the inside of the bulkhead pointed down (assuming the bulkhead is mounted on a side of the tank). Then drill a hole in the top to let air in -- kind of like a mini durso. Maybe do a 1" elbow to a 1" Tee then to the bulkhead. Have a cap on the top of the tee with a hole in it to let in air? Just brainstorming...

Jack

 

[TitansFan]

That would help for sure. how fast are you draining the tank? I know mine use to do this when my return flow was too much making the tank try to drain too fast.

they have a pic of what jack is talking about at http://dursostandpipes.com/
its under popular modifications -> external overflow

 

[crumbletop]

Great pic!

If you have enough room you could try it with the Tee on the inside (install like an upside down "T"). An advantage of it being on the inside is you can design it so if the water level keeps climbing it will eventually cover over the hole and create a full siphon which would then lower the level and FLUSSHHHHHHH. If the Tee is on the outside or the air hole is above the top of the tank, then a full siphon could never be established and you have a little more risk of flooding. Space may dictate what you can try, however.

 

[rcmike]

Yep, that's exactly what I was thinking about.

 

[Mobikob]

If you can't do the Durso idea, I think you could probably stop it by inserting a piece of airline tubing down the overflow until you hit the break point. that way the siphon will break beacuse of the air being sucked into the siphon. if there is too much noise from the air line, you can put a check valve on it.

I think I confused myself. did that make any sense?

Mobi

 

[Angela Short]

I am always confused but what about just drilling a tiny hole in the top of the 90 comming out of the bulkhead to let air in to stop the flushing or inserting a air line tube with a valve on it right to the top of the 90?
Or instead of comming out with a 90 use a tee and just cap the top portion of the tee and drill a air hole like a durso and the bottom half goes to the sump....Just guessing Lord knows I have spent WAY to much time in the plumbing aile at the hardware store this week!

 

[bkv1997]

I might be reading something incorrect, but is the exit of the frag tanks over flow under water in the sump? If you put the plumbing that drains into the sump above water level or very close to it that should stop the flushing.

Just a thought

 

[gflat65]

Alot fo great ideas, here. I'll start working through some options.

Brandon, the drain from the frag tank does drop below water level by about 1" or 1.5". I'll cut that down some and see if that fixes it. The biggest issue is that I need to pull the sump out and drill a larger hole in it and the fuge for better hydraulics. Then this thing will be a piece of cake. I'll try the drain fix first, as that might completely solve the problem.