The recommendation from the manufacturer is to install the tank vertically when possible. If not then the tank can be installed horizontally and they sell a mounting bracket kit for these applications. If your pump is cycling repetitively with very little time before starts again then it is possible that the bladder inside the tank has ruptured and the air charge is no longer present. To diagnose this, turn off the power to the water pump and empty the water completely from the tank. Use a pressure gauge to measure the air charge from the valve at the top of the tank. Typically the air charge should be between 28 and 38 PSI. If there is no air pressure or a low PSI value, the tank will have to be replaced as the bladder inside may have ruptured and is not replaceable. If you are not comfortable with this procedure, consult a licensed plumber in your area who can assist you with this.