my 4th aquaclear 70 powerhead in a about 18 months just kicked the bucket. they have the stupid waterline setup on them and if a little water evaporates from the tank you have to adjust them, i had two die last year from the water level slightly dropping so the third one i had gotten i decided to just dunk it a couple inches under to see what would happen and it was dead by the next day... so unless you have an over flow these are useless. they have about a 1 inch variance for the water level or they die... pain in the but... the worst is i had just setup a temporary 32 gallon for two small africans and two small male fronts so i could beef them up to go into my big tank... i was using the powerhead for oxygen, guess i should have known better becouse it lasted about a week and im not even shure why it stopped working. unfortunatly i lost the fish. no more aquaclear products for me