While many here consider my methods of 25 years ago to be primitive, I was able to keep not one, but two flame angels in one tank alive, healthy, and happy for 3 years. I also never had any problem with tangs (naso, achilles, hippo, yellow, atlantic) or angels, (queen, majestic, nemporor, koran, rock beauty, coral, the 2 flames, etc.). This on top of gobies, blennies, butterflies, even a Moorish Idol, feather dusters... They all thrived on brine shrimp and spinach.
Not to be rude, but I think some of you overthink this hobby a bit.