You can use the B&G Maintenance Kit as needed, but typically you would do a thorough cleaning about once or twice a year if you don't use your sprayer very often. For professionals using a sprayer every day, then you would do a more thorough cleaning once every 1-2 weeks or as needed.
Yes, the the nylon brush included in the B&G Deluxe Sprayer Maintenance Kit - Part 22049625 is able to fully clean a B&G 2 Gallon Spray Tank.
We apologize, but the B&G Tank Cleaner is not available by itself. We do carry a variety of other tank cleaners here.