further update

The good: no more sign of white poop. The not-so-good: yesterday I was tired. Made a few little mistakes. Refilling after the wc, new water was too warm. It bumped the temp up four degrees, yikes. I added some cool water, that just brought it down one degree. So I left the heater unplugged for a while. Checked a few times during the next few hours, was going to plug it back in when it started to dropped just below eighty (my target). Except then forgot, until I woke up in the middle of the night and remembered, and ran downstairs around 4am to plug in the heater. Tank was at 74 or 75°. This morning it's back to normal. Did a spot-clean again and found some pieces of broccoli leaf I'd missed yesterday. And the severum now has a faint white smudge on caudal fin, like a fungus patch is starting. Either the temperature drop or the leftover food fouling the water caused it. Damn. Going to be more meticulous now to keep the tank clean, hope this clears up quickly.