I run a 220g mostly fish only tank with 220 lbs live rock. I say mostly as I do have a few Kenya's and Green star polyps. I ran the tank at 1.009 (with refractometer) and watched all spots drop off - it took almost 6 weeks. The reverse fox face was most stubborn and its black body provided a great barometer as to how the tank was doing. I waited 4 weeks before raising the salinity - slowly raised it back to 1.025 over a 2 week period with no signs of ich returning. Tank had a mini cycle and was fine again after another 4 weeks. I have had a 90g quarantine tank with 5 tangs - an Achilles, a Hippo, and 3 Yellows. They have been in quarantine - untreated - for 2 months with no signs of anything, let alone ich. I put the Achilles and the Hippo in the 220 and within 3 days they had multiple small spots presumably ich -( the smallest ich resembling spots I have seen.) I have removed the 2 fish and placed back in quarantine, this time they are all getting hypoed in quarantine. I show no ich on any other fish in display. Would you expect my 220 still has ich and all the other fish are now resistant or did the tangs have it all along?
Let me finish by saying I know I should have initially hypoed all fish in quarantine and let 220 fallow. Not an option as my stock in 220 is - Porcupine puffer (7in) / Adult Emperor Angel / Reverse Fox face (7in) / Raccoon Butterfly (5in) / Needle fin Butterfly (4in) / Coral Beauty / Naso Tang (6in) / Valentini Puffer / Cleaner wrasse. And stock in the 90 is the 5 tangs - Achilles / Hippo / 3 Yellows. I couldn't have quarantined all these in the 90g!
Let me finish by saying I know I should have initially hypoed all fish in quarantine and let 220 fallow. Not an option as my stock in 220 is - Porcupine puffer (7in) / Adult Emperor Angel / Reverse Fox face (7in) / Raccoon Butterfly (5in) / Needle fin Butterfly (4in) / Coral Beauty / Naso Tang (6in) / Valentini Puffer / Cleaner wrasse. And stock in the 90 is the 5 tangs - Achilles / Hippo / 3 Yellows. I couldn't have quarantined all these in the 90g!