I just dipped 3 of my fish fish on Monday for possible vibrio; 2 genicanthus angels and a black and white chromis.
What I use:
Methylene blue & two 5 gallon buckets with their own heater and mini powerhead..
Bucket A-I use RO/DI water (FW) in one bucket and bring the temp and PH up to the same #'s that the fish I'm treating came from.
Bucket B-In another bucket use QT water. I usually keep my QT in hyposalinity at 1.010
Treatment
1-I add methylene blue, according to MFR suggestions, to the bucket with FW.
2-I take my fish and add them to the bucket with MB for 3-5 minutes. If they start to freak after 3 mins I take them out, with a seperate net, and place them in the QT water. I do this to each fish.
3- All fish go into QT for observation and possible further treatment depending on what I observe.
This works great for new fish to help with possible bacterial infections, flukes, etc.. I don't know that I would suggest this for Marine velvet. Marine Velvet is a very aggressive disease, which in my opinion, requires rapid treatment with aggressive meds.
This is my female Genicanthus Watanabei with a fast growing ulceration two days ago
This is her today. She was dipped two days ago. It appears as though the ulceration is healing.