I’ve never seen anything like this. Slime is everywhere ! Even in the skimmer. It blocked my skimmer pump! And main pump. This slime is everywhere. I’m waiting for UV lamp. Hope this will help This is completely disaster.
That slime is really common. People who run denitrators and carbon dose hope to see some. It's good coral food.
As others have noted, it is unlikely to kill or harm anything. The only real danger it poses is sucking up all the oxygen.
At risk of massive redundancy, forget about nitrate and phosphate for the time being. If you undertake a series of water changes, be especially attentive to the salinity (calibrated refractometer) and temp. The cure can be worse than the disease if you rush.
If the fish look to be struggling, increase the urgency of your actions. It's like going to the Dr. If your vitals are good, no matter how scary or disgusting your problem, they're in no rush. First do no harm
It’s with almost 100% certainty your experiencing a bacterial bloom.. a cheap UV filter will clear your tank quickly. Make sure you have lots of flow and point Powerheads/wave makers up towards water surface to increase gas exchange.
IMO your tank is absolutely way to young for all that livestock, I don’t care what you have been told or how you started your tank. Stop adding chemicals and let your tank balance and stabilize naturally.
The Green killing machine is a cheap UV filter alternative that’s a great item to have in your Reef tank tool box.. I will run them periodically when needed, the smaller ones can be had for less than $50.