Dt hypo treatment

[Mike-fish]

Hi all

I'm considering dropping the 270g into hypo to treat the ich problem I have currently. I'm currently dosing herbtana day 3 but I have little faith in it after doing some reading. The plan would be transfer the corals and nems to a holding tank during the treatment rather than tear apart the dt to reduce the stress on the fish. Then start dropping the dt to a sg of 1.009 for 6-8 weeks then slowly bringing it back up to1.025 over 2 weeks.
The stocking list is:
1 purple tang
1 one spot fox face
1 valigmi tang
1 powder blue tang
1 sailfin tang
2 clowns
1 copper band butterfly
1 cleaner wrase
3 chromis
2 fire fish

The only ones without ich are the cleaner wrasse and the firefish.

So does this plan sound good or will it back fire. Any thing else I should know about.