lookn good.
a co2 tank and regulator will charge it in less then 5 sec. but any air pump will do.
Valves and O-rings have lasted several years without any maintenance, (until I started using Citra pure, it make the rubber expand)
A charge will last much longer if you leave a little room for the compressed air or co2, if you fill the tank all the way full you will need to pressurize it a few times.
3 gal size is perfect for small jobs, I fill the 5 gal size up with 3 and a half to 4 gal of solution and that works for most jobs. and then I have a hand truck with two 5 gal and a air compressor so I can charge on location, great for large commercial VLM jobs.
all of my tanks max out at 110 psi, but the pressure relief valve usually pops at a little over 90psi (unless the o-rings have touched citra pure) I find my optimum pressure is 50-80 psi but am still comfortable at 80-90 and 30-50, anything lower then 30 and it feels like I am cleaning in slow motion.
Marking the tanks helps a ton, you can have different solutions in different tanks, and keep ready made protectant, deodorizer, or booster on hand.