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?