I have had problem in tank with a blackish algae for past few months and every snail dying along with any sifting fish like dragon gobies. After bringing fish store owner piece of my live rock he determined I had bad case of dinoflagellate algae that is toxic to all fish and inverts that eat it. Don't know how I got it but can't seem to get rid of it. Told to reduce lighting period and up the PH, hasn't helped much at all. Any thoughts out there?? This is getting depressing. 
