a bleached BTA is easy to save, provided you have pristine water conditions. A deflated, gaping BTA, on the other hand, is a lot tougher. That BTA you're showing still looks like it will be ok.
Alk is at 8.5 I keep it between that and 9 calcium is at 420, nitrates 15 phosphates are usually high as well at about .2 tank is about 5 months old I added it two months ago it’s a 40 gallon cube with two prime 16s for lighting
Far from dead and dont worry about CA or alk but rather pay attention to temp and salinity and PH
These guys only need the following:
Temp 77-79
Salinity 1.024-1.026
Ph 8.0- 8.3
Moderate light and water flow. and occasional feeding of mysis shrimp or similar 2x per week
I have lps and soft corals and they look great to me I did have some sps frags but they browned out or bleached I removed them from the tank about two weeks ago