I woke up this morning to find my purple & hippo tang with white spots on them mainly the purple. To me it looks like ick %&*%(. I have a 180 gallon tank and i am unable to dig out all the fish that i have in their and don't have a large enough qt tank to house all of the fish that I have. I only have a few inverts in the tank (still working on my clean up crew) just snails and crabs, and only a handful of corals some lps and sps. My question is how should I treat this tank, obviously treating them in a smaller qt tank is best but not a practical option. I was reading about doing hyposalinity treatment. I understand that most of my snails and crabs will probably die, worth the sacrifice to me. Treating with chemical would cost a small fortune and still no guarantee. All fish are eating like pigs and I will start soaking all their food in garlic and also raise the temp of the tank to help
The greatest concern about hypo is that it will kill inverts. Even if you don't care about them, the decay of their remains will cause ammonia to surge. Hypo that does not harm fish will not harm nitrification bacteria, but even a healthy nitrification filter can be overwhelmed.
If overcoming such a calamity is easy, people will not QT to eradicate ich.
There are still certain things you can do, and if you are skillful you can escape calamity. (If you were skillful you would not allow this to happen in the first place, however.)
1. Start a cycle with enough medium ASAP in a separate container, such as a plastic container.
2. Get two more large plastic containers to treat the fish. Alternate with 100% WC daily. Treat for a few days until ich is no longer life threatening, then return fish to DT. You may have to repeat this process a couple of times.
3. Generally, one has to balance the harm of ammonia with that of ich, both can kill.
4. Eradication of ich and the fallow period is a lengthy process, so a large QT with enough well-cycled medium and correct makeshift filtration will be needed to eradicate ich, especially in the case when infestation has already occurred in DT, not just prevention.