I have a high bio load in my 10 gallon nano , I currently run a aqua "C" nano on mine.. (
Welcome to AquaC, Inc. ) It is worthless , it does not produce any skimmate on my tank I have had it nearly a year with no more than 2 cups produced ,now you may ask why I continue to run it this is 2 fold 1: it adds flow and 2: it is there if something should happen to me that I could not maintain the tank. In my system I have 3 fish 2 clowns and a watchman goby .... along with various inverts and corals , I do a weekly 3 gallon water change with 1x a month hitting 4 or 5 gallons to change out .. I just think I keep up with it so much so that there is nothing to "skim" out ...others have suggested modding it with either an air stone or a higher GPH power head ... I have done neither as of yet

if you have no fish in it I would say it is not worth it as you will have micro bubbles that could irritate the clams or even kill them ... just keep with the weekly H20 changes and a large filter with plenty of CAG and floss (for chemical warfare ) and you should be fine