do not have to be directly under ... simpley put the return of the sump must be below the main tank
my very simple setup
doesnt really get any simpler then this...
flawless for 2+years thur power failures
drain is on the left return pump small mag5 on the right...
the first picture is the overflow... and the black tube going down.. the thing on the top that looks like a pump is a aqua lifter... that thing keeps the shipon all the time...
(you can hear it when you turn the sump off. slurping trying to start the water flow)
it does have to be primed the very first time.. (simply add water in the rear chamber)
the return line... from the mag 5
in the early days i had it all rigged
do it nice..(this is not) make it secure and steady the nozzle (this picture is litterly the first 30seconds of my sumps life) needs to be OUT OF the water.. or very close to the surface..
you can kinda see it here (i cant understand why outta like the 1000 something pictures of my tank i have on photobucket i dont have a shot of the left top corrner of my tank)
anyway
im useing Loc Line i have the nozzle about a 1/4 under the water... just enough to not slurp but makes a little whirlpool sometimes..
this is so when the power shuts off... the water sucks back down that tube a little (my tank drops about 1/2" down and my sump fills up almost to the top of the right most baffle...(well far from the top of the sump)