I am starting up a new tank, and I already have one that is established with a load of fish and they are doing well, and the water is crystal clear. Now how much gravel do I need to use from that tank to seed my new tank with the good bacteria. Will just a handful work? Becaue I have plants that are rooted and I wouldn't want them to be disturbed if I took half the gravel out. Thanks a head of time for your help.