Sump=pump

[Beans21]

Hi

Just got a 40g tank with 2 holes drill on each side towards the top . Can one of them work as the overflow and the other as the return ? Or do I have to get a overflow box?

Also, if this is ok, what size submersible pump do you recommend and brand. Probably about 2.5 -3 ft of hose on the return with a 10g sump (haven't bought this yet) .

Thx!'

[slief]

One could certainly be used for the overflow while the other could be used for the return. Personally, I would add an overflow box to one of them. If you don't want to do that, then at the very least I would do something like this.
https://www.customaquariums.com/information/h2overflow.html

http://i390.photobucket.com/albums/oo347/shleif/Tanks/IMG_3527_zpsqcajyioy.jpg

[Beans21]

Those are cool. A price didn't show up

Also will a 10 gall sump be good and what size pump will work

[slief]

Those are cool. A price didn't show up

Also will a 10 gall sump be good and what size pump will work

You would need to contact them for a price. As for the 10 gallon sump, that should be fine provided there is enough space in it to accomdate the excess water draining from the display when the return pump is off. If you have your return line high enough, there should be enough room but that will depend on the water level inside the sump and the amount of water draining from the display. You would need to calculate that.

[mcgyvr]

Go with a 20long for the sump.. or another 40 (40 breeder is the best small tank)..
The bigger the better for the most part but all can be made to work just fine.

[Beans21]

Thank you ! What size pump

[mcgyvr]

Thank you ! What size pump

In general one that is rated to push ~5x your display tank after head losses (see pump curve chart for flowrates at X feet difference from sump to tank).