well i ordered one of the black plastic j pipe returns and ordered the wrong size by mistake. thought i had 3/4 inch line but it was 5/8 inch so wouldnt fit on the 3/4-1 inch j pipe. the eheim did come with a one inch barb fitting, and i did have some extra 1 inch tubing, actually used alot longer peice of tubing then my 5/8ths and plugged it all back in, and now my lifereef overflow cant keep up with the flow. does the tubing really restrict the headhight that much? i mean this pump is only rated at 634gph at 0' head. the lifereef overflow is rated at 600 gph. in theory my pump should never be able to pump enough water to overpower my overflow. i never had a problem with the smaller tubing, but now im going to have to dial back my pump quite abit to be able to handle the extra flow. i guess these pumps are underated.