Right now, I'm in the planning stages of setting up my 120. I've never done a tank with a sump before, but I think it would be the best way to keep the budget down on this tank. I have a couple 29 gallons that were used to grow out fry and turtles and they are in pretty bad shape as far as looks, so would a 29 gallon make a decent sized sump for a 120 I should I look into a bigger plastic tub or something? Also, when I built the tank, what seems like forever ago, I never planned on a sump for it, so nothing is drilled. I've been going back and forth about whether I should just drill it now before setting it up (it's plywood on the back and sides, so it shouldn't be that hard to do) or go with so overflows that don't require drilling. I've already seen them in threads so I'll look around, but if anyone would like to post any ideas here, that would be awesome.