IMHO,
Return to very basics. Good CUC, micro diversity, and no products. Just good ole water changes weekly at 20% until things stabilize. Allow coral to be 1st in line for nutrients, once you are confident, then slowly address gaps missed in husbandry. In essence, a good skimmer should suffice if all basics are met. In a newer system, many focus on perfect water, which is what causes corals too starve, in quest of an algae free setup, which unfortunately is yet to mature. Cyano, is usually a n&p imbalance, this is why i would suggest getting back to basics, this is likely a sign of knee jerk reactions with over use of products. I would suggest weekly water changes , with discontinued use of everything except skimmer. Siphon cyano during water changes. Feed your fish, but not to over feed. Once balance is achieved and your corals are showing PE, then you can add carbon, but introduce passive, or low flow through RX. If your in(feedings), is more than out(nutrient export), then update skimmer 1st. Should this not be sufficient, look into your CUC. Lastly, install additional export resources as last effort, ie(c-source/bac source dosing/ gfo). Personally, I prefer to use a quality salt over all others, with consistent water changes, mixed to as close to where I prefer maintained parameters. This way, larger water changes to not cause fluctuations. I also prefer a balanced salt, one that has trace balance as well. No need in dumping trace, or other products, to accommodate an inferior salt, just my 2 cents
Cheers
