I'm currently setting up a 150 gallon tank with sump. It has sand and I've used stability daily for 4 days.
I also have a 55 gallon reef tank that has been up for a couple months. A have a fish that has Ich. Could I put him in the 150 and treat him and put him back in the 55? Then remove any trace of Ich or copper from Ich meds in the 150?
Ich can only be solved with either hyposalinity or copper medications. This has to be done in a QT tank as both will kill inverts. The copper leaching into the rocks and staying there. This needs to be done for 6-8 weeks as this is the life cycle of ich and the only way to ensure it isn't in the tank anymore is that the display is fallow for this time.
In terms of the ich, I would start looking into why the fish is stressed. Be it bullying or parameter issues.
Why not move everything in 150 gal except all the fish and treat them with copper in your 55 gal? Leave the 150 gal without fish for 6 weeks and by that time the fish treatment is complete and can be moved to 150 gal.
"Nothing great in the world has ever been accomplished without passion". George Wilhelm Friedrich Hegel
Yeah, that is the only way to address ich when it takes its course. It is a 6-8 week period of the tank being fallow that it will no longer be in the display. But you might also want to look into why there was ich to begin with, be it stress or parameter issues.