Blacking new bulbo growths

[sunfire]

Ah! I am upset. This new growth was doing really well but now it is turning black (must be in last 2-3 days). There’s another small growth in the back that has a similar appearance. Fungus? Advice? Should I remove it?

This is potted in long fiber sphagnum moss with LECA on the bottom and sitting in a few millimeters of water. It is inside in a garage under grow lights getting about 800-1000 foot candles. The temperature is around 80F with humidity around 50% (was higher a few days ago because of the rain). I had it under a vented plastic humidity dome as well. It is watered with RO (TDS 5) and fertilized with MSU RO fertilizer at 25–50 ppm N. The last watering I used to Kelpak and quantum total.

All advice appreciated. Thank you.