If you don't have any inverts or corals you can do Hyposalinity right in your current tank setup for 3 months to get rid of it.
There are a few concerns with this method:
1) Velvet is often misidentified as ich (not effectively treated with hypo)
2) Brook is often misidentified as ich (not effectively treated with hypo)
3) There are strains of ich that can survive hyposaline conditions
4) It can be difficult to keep the salinty in the narrow-band required to traditionally eradicate most strains of ich. If the salinity rises above this (as water evaporates for example) for even a few minutes, ich can complete it's life cycle thus nullifying the "therapeutic time" prior.
A much better course of action would be Chloroquine Phosphate in a 40B or Copper (Copper Power and Hanna Copper Checker) in a 40B. Biospira is a great product for kickstarting bacteria and it's readily available. Fritz Turbostart 9000 is better but much more expensive and not available in many stores or even
amazon yet.
Since the Hanna Copper Checker was "discovered" by
@HotRocks as being immensely accurate for ALL forms of copper tested -- we can keep the therapeutic level therapeutic but not overbearing. We've learned that the most commonly used copper product "Copper Safe" prior had IMMENSELY varied potency depending on the bottle used and you could be dosing 3.0-5.5 PPM copper by following the instructions on the bottle (as we have confirmed). Occasionally a bottle was correct in "potency", but the next one would be completely different and previous copper testing methods left a LOT to be desired and even if tested most wouldn't be able to tell 1PPM from 2.5PPM on many tests.
All of the above led to people keeping fish in MUCH higher copper concentrations than necessary which I believe is what led to many copper deaths (myself included). Now that we can keep the levels at 1.75 EASILY with the Hanna Copper Checker and Copper Power -- it's been a MUCH easier road with dozens of fish through without much issue.
The new problem we are seeing a lot more of is bacterial infections and Uronema. Both are much more deadly than ich or velvet and horrifying prospects. I'd keep metroplex and spectrogram on hand.
