overflow boxes...

[Terry64]

I just recently fitted an overflow box to my 55G, the problem is that it won't allow me to fill my tank up, if i tuck the box right up under the inside lip of the aquarium, the system sucks all the available water out of the box then air gets in and stops the system working, if i lower the box in the aquarium all is fine but means i have to have my water level about 3" from the top of the aquarium, i am puzzled?

Terry.

[Mike O'Brien]

Sounds like you need a stronger pump. what are you using

[muddybluewater]

It might be a water level issue between the two boxes. When you have the inside box lowered and the pump off does the siphon stop or will it restart by it self when you turn on the pump? Can you post a side view picture?

[BigJim]

Are you using an overflow with a "J" tube?

[Terry64]

Yes, a 'j' tube connects the 2 boxes, it's almost like the overflow box isn't big enough? do i need a bigger one to hold more water? the box is being emptied faster than the water in it can be replaced.

Terry.

[Spyder]

Something just doesn't make sense here. Can you get some pics of it? I am curious on how you have it set up.
They are pretty simple and I am very confused about how you are having trouble with it?
It really should never break siphon unless it is unattended for a long period when the return pump is off.

[Terry64]

i don't know how to do pics....sorry.

let me try again to make sense, i have the overflow outside box fitted, i also have the inside box fitted but when i put the inside box right up under the inside lip, it runs for about 1-2 secs then the 'U' tube fills with air and the syphon breaks, if i put the box about 3" from the top resting on some rockwork, everything is fine but obviously my water level is also 3" from the top.

Terry.

[Spyder]

What OFB do you have?

[Terry64]

not sure, it's black is all i know.

Terry.

[Fiji Live Rock]

I agree with Mike. It sounds like your return pump is not strong enough to keep up with the outflow of the overflow.