Terence off this subject but qwill there be a lot of these pumps delivered soon in January, My tank will b e delivered about around the 10th and If I can't get it then I will go with sicce had good luck with themExcept that the limiting factor is that the pump must be able to have the PSI to push the water through the constricted pipe. Larger diameter pipes are almost universally better. Again, think about it this way, would you rather drink a milkshake through a 10' 1/2" pipe or a coffee stirrer of the same length? Of course there is theoretically an amount of work that can be performed to get the same flow rate between the two diameters, but clearly one will be far easier.