well, hypo kills bad stuff, but also kills good too - including all inverts, pods, and beneficial algae too. So the rock has to come out - I have the rock in a large tub with PH's and heater. water in tub is SG 1.025.
Ideally, you would even take out live sand, but that is virtually impossible obviously.
Overall, it's no fun... and it would be easier to just take the fish out and put them in a smaller hospital tank... but doing that is more stressful on the fish. So I decided to leave them all in and just take out 90% of the rock.
Things are still going good! Everybody looks quite healthy!