Whats happening to this torch?

[ab-774819]

I've got a little torch garden going and all are doing well except for this one. It just started within the last week and has gone down hill fast. I've had it for approx 6 months and it has done well until now. I initially noticed deflated looking tentacles, then receding of the tissue and now it's melting/losing tencles and flesh completely on 2 of the 3 heads. The 3rd head looks completely normal and healthy. I added photos of what it looks like now vs previously.

Perams as of 12/4/23
Alk: 9.4 (have always kept it higher for acro growth)
Po4: .08
Mag: 1410
Calcium: 480

 

[Lavey29]

What are your nitrates?

 

[ab-774819]

What are your nitrates?

I only have an api test for Nitrate but I'd say 5-10ppm