dieing open brain/ nitrate spike

so my open brain has been dieing for the past couple of days. i have no idea as to why. the nitrates were at nearly 0, then once he started to go the nirtates sky rocketed to 40, this is even after 5 gal water change the first two days and 10 gal change yesterday. my parms were good (couple of things were low) [ Am >0, No2 0, No3 40 yesterday almost zero before, dkh 11.2, mg 1050, temp average 79 with no large jumps, salinity 1.024].
i did just add a tomini tang 5 days before, he wasnt bothering the brain till it started to shrivel. my clowns were hosting it. about day two into the shrivel i noticed that a piece of flesh was moving in the current and not attached but i dont know if is because of it shriveling. the brain started to shrivel about a day or so after the my BTA moved away, before he was almost on top of the brain. and i had seen the tennictles touch the brain a couple of times. I dont know what is going on, the brain was looking great before this. the whole thing is very random. not to mention that all my other corals are doing great. any ideas what is going on here? p.s. i think its to late to save the brain...*sniff sniff*

 

what kind of lights are you using and what are your other levels? ie..Mg, Ca, Str., Iodine, all the normal stuff you should be testing for when you have corals...... how long are your lights on for also... and what is the placement of the brain?

 

ohh my lights are new 150 Mh and 2 39 watt attinics, and ca mg all that stuff is ok. we figured out that the my BTA poisioned the brain. he had stung him a couple days eariler and the only reason the brain was puffy was as a defence mechinism. and the rotting brain was causing the No3, Am spike.
i luved that peice of coral