Most likely, those people treated the ick using copper or hyposalinity in their main tank. The copper will do in corals/inverts, and the hypo if done correctly probably will also. I'd keep an eye on your fish to make sure the ich doesn't reappear. Seems like any remedies other than copper/hypo are kind of hit and miss as to their effectiveness. Ich will drop off the fish and appear to go away, even without meds - so just be vigilant.
Regarding the possible diatom bloom, have you changed lights recently? Seems like when lights get old and they shift their light spectrum, some folks can have algae issues. Same goes when they just replace them too!