First, the best place to treat Crypt is in a bare bottom QT tank. No rock, which will absorb the medication.
Second, there’s no need to further stress the fish by cranking up the temp. Normal 78-80 degree water temps are fine.
Copper is still a good choice to treat Ich provided the fish can handle it (not all fish can). I like Copper Power (a chelated version) but you can use an ionic one like Cupramine if that’s what you have. You can also use the tank transfer method on sensitive species, but it requires more work and multiple QT tanks.
If you go the copper route, remove any activated carbon from the filter. Slowly raise the copper level to 2.0 to 2.5 ppm (if using Copper Power, or 0.5 ppm with Cupramine, and depending on the sensitivity of the species you’re treating) over the course of 4-5 days. Keep it at that level for a full 30 days. You’ll need a copper test kit to ensure the level doesn’t drop below therapeutic. If you perform water changes during the treatment period, you’ll need to add copper to the make up water before pouring it into the tank.
There is no reason to add additional salt to a saltwater QT tank.
