the option always exists to simply force the tank clear and not id anything. We do skip cycle cleanings for all sorts of reasons: upgrades, moves, emergency tank builds to handle cracked display tanks, and in your case just to make it look perfect again. We have done no less than hundreds of them and most are cataloged in our peroxide threads. its a lot of work, but wow does it reset the tank and last a long time. it involves taking rocks out and holding in buckets of clean sw, fish in other buckets, then take the whole tank apart and rinse the sandbed 100% until it is cloudless. refill the tank with all new perfect water and that cloudless sand. rinse the rocks off well in their holding buckets, put back in, corals, reacclimate fish, done.
there is no age limit you can do this on a tank. once your tank can handle the bioload preferred and show zero ammonia, that's the starting point for this kind of work doesn't matter if the tank is 1 day after cycling or 11 yrs old like my tank that gets this 3x a year (so that I can neglect it and stay gone mostly, I use rip cleaning as catch-ups for not doing normal care)
you can use them any way you want, we've never lost a tank to a recycle. as a matter of pride we skip cycle all the rebuilds. anything from two part doser interaction to sandbed issues (silt) to bac blooms (very highly rare if you aren't dosing carbon) can cause that. algae blooms due to direct sun access is most likely candidate imo