Yeah, something was wrong. Pulled out the chaeto, and the bottom of it was black and smelly.
pulled the live rock...something stank.
I'd have to say it was likely anaerobic pockets, as some of the LR
has black spots on it, and it stinks like rotting something. the sand was really bad once I disturbed it.
I'm letting it set out overnight to completely die off so I can scrub it tomorrow (hot water only), plus i ran outta w/c water, so I'm making another 5gals to refill it tomorrow.
Interesting to note: my brown button polyps that have been sad looking for some time now...actually opened up fully and extended their tentacles! they haven't done that in ages, no matter what I tried to do to accommodate them.
hopefully this'll make the tank take a turn for the better.