Iodine and phyto (preferably live). I use DT and Purple Up (Iodine and Calcium). I have huge rampant colonies of madly pulsing xenia. If you lose yours I have some up for sponsorship in the Pay it Forward program. You can look at the pictures there that I will be posting in a few moments. Tanks doesn't have to be dirty, they just need to be feed and they also like iodine IMHO.