why did my chaeto die?

[mayjong]

so, i've had the same chaeto for over a year. probably closer to two years. it has been with me throughout my biocube venture and is/was in my cube. all the while growing, and being trimmed. no issues.
i trimmed it about 3 weeks ago. went to check it yesterday and it was dead/dying (limp, slimy, etc) ca450, kh 11, mg 1450~~ lit by a 6500 "home depot" bulb
i removed it.
any ideas?

 

[mayjong]

btw-
all sps, lps, zoas doing fine

 

[noobofthereef]

What are your nitrates? Maybe it couldn't use up nutrients to grow anymore.

 

[mayjong]

dunno. i don't own a nitrate test.
if anything i overfeed and i assume my tank runs "dirty". i do have flame algea in the dt that is fine. other nuisance algeas are growing fine (wish they weren't)
this one is really strange to me. the only thing i can think is that the last time i trimmed it, i had to do a little bit of repair on the netting i use to contain it, it was exposed to air for longer than normal. i guess that could be it....
hard to say when it started going downhill, i can't see it where it is, i have to reach in to grab it.