One thing I didn't see in your test results is salinity. You mention that you buy salt water for water changes, does that mean you're not using RO water for top-off?Thank you all for your help, Ill start doing water changes weekly.
As others have suggested, regular small water changes will likely improve things substantially. I understand that you're not particularly interested in more corals, but the health of the ones you have are probably indicative of less than optimal conditions, which are likely adversely affecting your fish, even if you're not seeing any signs of it.
Good luck in your quest to turn things around, seeing people leave the hobby through frustration is never a good thing.