Cyano Outbreak, while on Vacation?

[SteveMM62Reef]

Went on a nine day vacation. Four days before I did a through cleaning. Three days before leaving a 20% water change. Changed filter socks out the morning we left. 120 was just on its regular scheduled auto feeder, no change to this schedule. The Fish, didn't get their almost daily frozen food. Also no ReefRoids. ATO was on, and salinity was fine on returning. Filter Socks were overflowing, mostly from the Cyano. Changed filter socks out, and did another 20% water change. Today will be the final day for ChemiClean treatment. Just wondering what went haywire?

 

[isaacfish]

Hi how long have you had the tank?

 

[isaacfish]

And what type of water did you use to do the water change

 

[SteveMM62Reef]

RO/DI at a TDS of 1, my Usual Reef Crystals, slowly added to assure mixing. The mixing brute shows no signs of Cyano. Aquarium was filled and started on 6-27-2022. With mixed media sand bed, dry rock. Was seeded with water, gravel and live rock from a well established 65 gallon aquarium. Also the Ruby Sump/Refuge, was already up and running on the 65 Gallon for at least a year. Lighting hasn’t changed in months. I did add a Rescued Mandarin, a couple weeks before. All fish are fine. I don’t do much testing, found I was just chasing parameters back and forth. I do monitor pH with a probe.