you can get check valves from petcomart or the lfs.. walmart might even carry them..
get a few they are cheap.. attach one to the pvc with the sucktube attached to it and then a second one on the end... (they tend to fail.. or they did for me anyway)... you can also just tuck the tube under the water level... however that means you are going to be sucking on something that was sitting in yer tank for a while.... (eww) and depending on what you have for fish they might try to make a snack out of it..
as for yer sump... also looks good.. is it big enough.. 1/3 the capacity of the tank is a number that is in my head for some reason... i could be making that up though..
you can always get a bigger tub.. not a big deal.. all comes down to what you stock the tank with..
Does the rest of the tub matter? Only a 50 gallon rubbermaid, but that's just adding to the gallonage isn't it? Will the 15-20 gallons of pot scrubbies do well enough to filter?
That's good, I'm still trying to get it up and running, overflow keeps quitting after the waterlevel catches up with it, my pump can't quite matchup, how do you keep the siphon going after the water level gets that low?
That's good, I'm still trying to get it up and running, overflow keeps quitting after the waterlevel catches up with it, my pump can't quite matchup, how do you keep the siphon going after the water level gets that low?