You don't think it could be the gfo ripping po4 out too fast?
Ive read that a tank must be acclimated to low po4 levels. I started with a teaspoon of gfo and you only have maybe 15-20 more gallons than me. How much did you use?
Link - http://www.nano-reef.com/forums/lofiversion/index.php/t297880.html
Don't birdsnest sometimes die off once they get to a certain size? I've heard of colonies just collapsing for no reason.
81 is a good temp as long as its constant. In your case im sure it is. Alk could have rocketed higher when the BN first started to RTN. It could have leveled out. It may have been from GFO or something else. Honestly, if your acros and other SPS are lookin good I wouldn't worry. Ive read that BN tend to die off as they mature anyways. Maybe something triggers it, but its a BN. It will be grown out in no time. good luck Smitty.
BTW.. im loving that new Wrasse.
Heard the same thing.
Smitty, I have a large colony of pink/yellow/green birdnest that I can break you off a chunk if this one doesn't make it.