If you switch between low and high you may need to retune a bit. Can't say for sure as I don't own a demon. No biggie, just keep the same tank on it all the time and you'll be rockin.
Etek 3LT grey/black f/s
Valken Proton greyish/black f/s
68 4500 PE stubby, LP output f/s
68 4500 AIR tank(no reg) f/s
Creed Battery, eyes and noid f/s