Dino problems

So I bought a setup that had a bunch of nems and some corals already existing. I didn’t want to use the existing rock/sand/water but had to under the circumstances. Now the tank seems to be cycling with a terrible Dinoflagellate brown slime that I can’t get rid of. Any old pros out there have any ideas?? I’ve turned the lights off and am doing water changes biweekly now. It comes back overnight. I’d rather be dealing with briopsis to be honest…(disclaimer, I don’t know if it really is Dino’s or not but it’s the only conclusion I know of that makes sense)
 
Reef Flux for byropsis algae is a simple fix.

Not sure why you mention that in combo with what you describe. Hmmmm.... cyano comes in different colors, but usually red family (but brown isn't that far off red...). Perhaps this video from the club's DFWMAS YouTube channel will give you some helpful dino (IF its dinos) info:
 
Reef Flux for byropsis algae is a simple fix.

Not sure why you mention that in combo with what you describe. Hmmmm.... cyano comes in different colors, but usually red family (but brown isn't that far off red...). Perhaps this video from the club's DFWMAS YouTube channel will give you some helpful dino (IF its dinos) info:
I mentioned briopsis because that used to be the most frustrating…
 
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