no sump??? improvised lol. i used to hv no sump, till i die die squeeze a 1ft x 1ft x 1ft tank out to be a sump and utilized an I-Box for overflow.
alternatively, u can look for a HOT which u hv suggested. heard the macro needlewheel is not bad. economical and performance wise. gotta ask the bros who r using this or search for a review on this. if ur budget is not tight, maybe can consider aqua c remora pro, deltec hang on, aquamedic multi sl.
juz me 2 cents.