A bit confused on how to proceed. This tank in one form or another has been running for 10 years. (was a 10 gallong, then a 20 then had to change the 20 as it was leaking)All was pretty stable till about a month ago. We had been running a canister on it and the motor was dying and nitrates shot up. Like over 60. The canister was since replaced by a hob. A 20 percent water change was done and we kept eye on nitrates. It just plumetted every day. It is now undetectable with salifert test as is phos. A brownish reddish substance now grows on the rocks. It is not very easy to remove but I keep trying to take it out. Goes mostly away at night. Caleurpa racemosa was added when nitrates were high and it grew quickly. Stopped growing after nitrates were gone. I have removed it because my pretty pink macro algea that came from god knows where was wilting and thought they were fighting for nutrients. The tank is 20gal with 10 pounds of liverock and one chunck of artificial but that has been in over a year. There is a clownfish and a neon goby. 3 blue legged hermits, a few mushrooms and a gsp. The gsp has stopped growing as well. Using aquaforest reef salt for the last 6 month or so. There is a wavemaker on each side and cranked the flow to ridiculous and it did not help. There is a bubble magnus miniq skimmer. I am way over feeding the fish in an effort to increase nitrates and they are round balls. No water changes for over 2 weeks and still no change. Coraline is bleaching and dissapearing as well and they brown/red stuff growing where it was.I am in no means an expert and my tank just kinda thrived for a long time with no issues. Unsure what to do even after loads of research. Is it cyano? Dino? I have put in some microbacter7 a few times. It has always been a simple stable tank. What am I doing wrong? Thanks for any help.