Aqua Ultraviolet lamps are designed for 14 months of continuous use. Flow rates are calculated at 30,000 µw/cm² , based on the end of useful lamp life. Since we have calculated our flow rates based on the end of lamp life, there is no need to adjust the flow rates during life cycle of your lamp. Aqua Ultraviolet’s unit will perform at its optimum through out the life of the lamp and it just makes it simple.