After TONS of reading on forums I settled on three quarantines:
I do the Hybrid Tank Transfer Method.
Important: Tank Transfer Method is most effective when water temperature and salinity are kept within this range... Temp: 24C/76F - 28C/82F Salinity: 27ppt / 1.020 SG - 35ppt / 1.026 SG Tank Transfer Method is an effective (non-chemical) treatment for Marine Ich. However, it's weakness has...
humble.fish
This covers most problems and if your lfs is sourcing fish from a quality vendor you may experience less issues.
with TTM the fish is in quarantine for 13 days.
I have a cheap light that i have set on a timer, the tub has RODI water, a heater and a pump to circulate water. I have an air pump and an air stone that is replaced every 3 days. Super easy to setup and maintain. the tubs the fish are in are 2 gallons. Enough to keep ammonia down for 3 days and if its a bigger or more fish i have prime just incase. i feed sparingly. after the three days i transfer the fish, rinse the tub and throw it in the dishwasher on a sanitize cycle
snails and crabs have a 10 gallon tank i kind of neglect. they stay in there for 6 weeks and corals I just dip.