When I added Rotala Macandra to my tank I also began iron supplementation to help it retain its color. About two weeks later I noticed Riccia growing amongst the Dwarf Hairgrass. I would remove it periodically, but eventually it spread everywhere! Each week I remove about a cupful from my 29 gal tank. Is this connected to the iron supplement, or did the Riccia just come aboard with the Rotala Macandra? Is there some method other than constant manual removal for dealing with it? Thanks