[LeonardS]

It’s not really the compressor tank size that’s as important as the cfm output of the compressor pump. It takes a lot of air to run a sandblaster. I would keep the 15 gallon one so you don’t have to refill it so often. Also make sure you have a good air dryer or the sand gets damp and plugs the nozzle. I use sand or black blast in my pot blaster.