I feel the worst misconception is buying Dry rock labeled as liverock and thinking they can get natural ecosystem with bottled bacteria! We absolutely need to seed our tanks with established LR (at minimum with sponges, fan worms, coralline).
-Mostly all the bottled solutions are an issue for me. They seem to just be playing mother nature, Chemiclean, Vibrant, etc!. If its not a trace element that I know is depleted, its not going in my tank. I remember for 10 years in my FOWLR tank, i dosed kent essential elements bc someone told me Protein skimmers remove trace elements.
-You have to setup a QT - otherwise your not a good reefer. Seriously, i heard this for 20 years when I didn't have a QT. Like how is someone new thats barely able to succeed in a display tank going to have the experience to succeed in a sterile QT tank! They should just buy QT stuff or from a reputable source.
- LED doesnt grow corals
- I absolutely hate Biopellet reactors (very risky), I hate GFO (stop overstocking your tanks, get rid of sand, increase flow, get a Refugium), Nopox, all that stuff. Phosphates are good for our corals! I must admit I am a big Chemipure fanboy - best carbon by a mile and worth the high price.
Trident method - pushes that you can avoid water changes with their system, NO one can avoid doing waterchanges, we can just prolong them long time,
Ultimately, I stick with a proven method as the Berlin method, (protein skimmer, rock, flow, refugium, and Kalkwasser). These method are natural as can be and less prone to crashes. i think the one thing that doesnt get pushed enough is cleaning pumps or propeller pumps. The slime that forms on our pumps reduces flow so quickly that a point should be made to change them monthly or minimum every 6 months. However, most ppl dont remove for cleaning for years at a time. This itself will ensure nutrients stay in check and things are stable long term.