I have to say that in the 6 years we have been using them we have changed out due to leaks 2 times... Of course because my tank, though on the cement floor, is surrounded by carpet so leaks show themselves about the time the carpet is wet! Sometimes I think that because of the amount of water in the sump the sides tend to bow out and that put stress on the seams.. they were never ment to hold water for 6 years! lol Plus the heat from the pumps ect.. But for the money they are worth it. Now that we have one inside the other, kinda doublewall construction idea, we haven't had a problem. But what do ya do with all the stupid lids you don't use! lol