The floating bag only acclimates the temperature to your tanks temperate. The drip acclimates them to the actual water parameters of your tank (salinity, etc.).
I think the JV Tang should be kept in like 100+ gallon tank. Your profile says yours is 55. There are many here with more expertise than me, but maybe that could have been the issue.
54G AGA Corner Tank
Eheim 2215 Canister Filter (w/ live rock rubble in it)
3 Maxijet 1200 Power Heads
Aqua C Remora Protein Skimmer
Acqua C Remora Pre-Skimmer
75 pounds Live Rock
30" 2x65w Coralife Lunar Aqualights
Turbo Twist UV
2 Percula Clowns, Diamond Golby, Flame Angel, Royal Gramma, Lawnmower Blenny, PPmint shrimp, 3 emerald crabs and a huge cleaning crew (snails and crabs)