My LFS can get me fresh water clams on the cheap and I was thinking of getting them for a few of the tanks. One of the tanks I wanted to use them in was my 75 gallon planted tank but not sure if that would be a good idea since I spent good money for substrait to keep the plants happy. So can I add them and not have them siphon all that paid for to keep my plants healthy or should I just leave em out?