Overflow Box Too Small?
 

If I had to do it all over again I think I would buy a tank already set up. However my time machine is in the shop so here goes "I need help! Part XXI".

Bought and installed a pair of overflow boxes for my 125 gallon. Seemed simple enough just make sure they are big enough to get your hands around the stand pipe to remove when needed. 5" square should do.........wrong! With the teeth restricting flow over the lip I am not getting enough water to the sump. Aquarium fills to the point where the water is going over the top of the teeth which sort of defeats the purpose. Options?

1. Remove the teeth?
2. Remove the boxes and get them enlarged?
3.?????

Any opinions appreciated.

what size pump are you running?

Mag 24 with 2 x 1.5" drains and 5' of head. I am looking for 1500 gph and my drains are able at least that.

Seems to me the bulkheads can handle that amount of flow but your overflow boxes can not. What are you overflows rated for? Should say on the box I would think.. :confused:

Is drilling the tank an option? Thats what I would do if I were you.
If not you have two options.

1. Get a smaller GPH rated pump that the overflows will be able to handle.
2. Return the overflows and get larger ones or DIY larger ones.

Bulkheads are definetly big enough so I won't be drilling more holes. I guess its bigger overflow boxes. That sound is not my sump its me flushing more $$$$$ down the toilet. :cry:

post
 

Try taking ever second tooth off the over flow boxes.

Muck, I just read another post where you mentioned you don't use teeth and cover the top with gutter guard. If I cut the teeth out I might be able to get the flow I am after.

Nemo, Cutting every other tooth out might work but isn't the point of the teeth to keep out snails and fish?

Yes but didn't you write you wanted to try and not spend more? Or another thought cut your teeth deeper

Is it a straight pipe out of the overflow or have you used any elbows, etc?

It sounds to me like the pipe is restricting the flow not the box.

Call me at OA if you have time.


Wendell

The water that goes over the overflow quickly disappears down the pipe. The water level inside the box is slightly above the standpipe but still below the top of the box. The drain could take more water if needed.

Sounds like the box then.

It just surprises me that the box at 5x5 would restrict the flow that much.

Call me if I can help.


Wendell

Are the boxes 2 sided corner overflows ? or centered 3 sided ?

Im guessing the spacing between the teeth is the problem.

They wouldnt happen to be a "saw blade" width slots would they ?

Fudge, the teeth are 5/16" and the box is 2 sided. I have fixed the problem and now it works fine. I have used a high speed rotary saw (big dremel) and cut the top of the box off 3/4" below the bottom of the teeth. I then glued the removed L shaped peice to the outside of the box. This lowered the top of the teeth 3/4" and provided an extra 1/2" of lip length per box. The extra 1" total lip and the lowered box height seem to handle the flow now. For those looking at adding boxes to their tanks I can say that the calculator on reefcentral for overflow length is a good starting point. It recommends 23" of total overflow length for 1500 gph. I had 22 and the water was just cresting the top of the teeth. I now have 23 and the flow is just below the top.

http://www.reefcentral.com/calc/drai...0&drain=Submit

Thanks for all your help and tips. :biggrin: