The only routine maintenance required on these tanks would be to check the air precharge in each tank periodically. This would be at least 2 times a year, fall and spring.
This is done by turning off the valve on the water line into that tank, connecting a hose (should be in place normally) to the drain and completely draining the water from the tank. When the tank is completely empty, use a tire gauge to measure the pressure in the tank at the valve on the top of the tank and adjust as necessary. A compressor and tire chuck can inject air into the top of the tank.
The air pressure in each tank, when completely empty, will be 35 psi. Adjust as necessary.
Installation and setup instructions can be read here.