will this work???

[shrimpin]

I have a 27 gallon tank with a HOB and I dont like it, so I bought a overflow box and had a 5 gallon tank, it was the only thing I could get to fit under the stand.

Anyways I wanted to still do something benificial for the tank so this is what I came up with....

(Sorry that the pic is so bad, I had to draw it on Paint)

[Sploke]

Well, what you need to look at is how much drain-back you get from the main tank when you turn off the return pump. This will include water left in the drain lines, overflow box, and a thin layer of water in the tank that will drain down. There isn't really any way to calculate it, you just need to try it and see. I'm guessing that while running, you could get maybe 3-3.5gal of water in the sump..if you have it sectioned off, you're going to be topping off the return pump compartment pretty much every day, since all loss due to evaporation will come out of that compartment. IMO I would go with something bigger, I think that a sump that small would add more headaches than improvements to the system.

[shrimpin]

i already have to do top offs daily anyway, and would this still be a better alterinitive to a HOB thats about to break??? It almost just seems like a canister that can carry a larger volume of water....

[archer772]

Yes it is much better than a HOB filter IMO. You might be able to make the feed side for the sump small and add to the return side. I am useing a 10 gallon for a fuge and I have about 6 inches for the skimmer, 4 inches for the macro and then the rest for the return and it works good for me.