Overflow box (1 Viewer)

[dvs]

Need some help on overflow boxes and sumps in general. I am going out of country this summer for 2 months and I need to make sure that in the event of a power outage my tank will keep siphon and not spill water all over the floor. Currently I have a 75 that is filtered by a rena filstar. I just built a sump and now I am looking for an overflow. My question is, do I need to have some kind of pump connected to the weir in order to maintain a siphon without worry? In other words, will any overflow box that I buy with a u shaped tube keep a siphon? I checked out melevsreef and he showed a powerhead sucking air out of the weir. This is what has me confused/concerned.

Advice please!

 

[altimas]

A powerhead would keep air from accumulating in the siphon tube. Then again, that means you'd have to have an overflow that has that hose attachment to connect to the powerhead.

I've got an overflow from aquatraders, but it's only been running for 3 months so I'm not too sure on the reliability.

One thing I've noticed is that if you have enough flow in the overflow box, then the bubbles will not accumulate in the weir to the point of breaking the siphon.

On the other hand, on my overflow box, if I set the flow too slow, then bubbles would accumulate to the point of breaking the siphon.

 

[dvs]

Well I did not think about that. More flow would likely push the air out. Do all overflows have adjustable flow? How do you adjust flow? Pardon the noob question.

 

[altimas]

Well, one way to adjust the flow for sure is to have a valve on the return pump.

The best way to do this would be to get a "T" connector and put the valve on the line not going into the main tank. I think there are pics on melevsreef.com. That way you won't shorten the life of the return pump.