Ive attempted to remove Amphidinium for a few months now. Ive done a few routines and over the past few months added a lot of bio diversity to my tank. It seems no matter what i do they come back. Ive nearly vacuumed out a third of my sand bed. Im curious if anyone has taken out all their sand and had good results. If so, did you add sand back? I plan on dosing Si as soon as i can get some as well.