Sorry to read about the ich problems. Nox Ich is my favorite medication for ich and will blow the heck out of the ich, but it'll stain some plastics, including silicone, a nice green color. It's also potent, so be very careful with its use in any tanks with thin-skinned fish (catfish, loaches, etc). I've only had to use Nox Ich twice in my life, but I've tried the other remedies (heat, salt, etc) twice as many times and never found them exceptionally effective.
I've read/heard about ich always being present in every tank. Not sure I agree 100% with that statement, but I believe the potential for it is very common. Despite that, I still try to be careful where I get my fish from. For example, if a LFS has something really nice, but it's on a shared water system with another tank in which a tetra has a few spots of ich, I simply won't buy without the expectation of keeping the fish in a separate tank for 4-6 weeks under supervision and being ready to medicate if necessary.
If you have a sick fish, be very careful about sharing any nets/breeder nets/rocks/air stones/etc between other tanks for fear of transmitting the ich. Items should be sterilized before use elsewhere.
Is the 76F stable or does it fluctuate? If it's dropping to the very low 70s, the fish might be more stressed and become susceptible to ich.
You mentioned that you do frequent water changes. When you do water changes, I'd aim for water temperatures at least as warm as the tank, if not slightly warmer. I always strive for slightly warmer, but only check by hand, not with a thermometer. (Be careful to not going with really warm water, especially if it's a large water change (>20%) as it holds less O2 content).
P.S. my edit in the original post was to correct the spelling in the title.
