To find the optimum "Desired Output %" setting, start at approximately 50%. Test the chlorine level every few days and adjust the dial up or down accordingly. It usually takes 2-3 adjustments to find the ideal setting for your pool/spa and after that, it should only take minor, infrequent adjustments. Because the chlorine demand of the pool increases with temperature, most people find they have to adjust the dial up at the peak of the summer and down during the colder periods. The Aqua Rite automatically stops generating when the pool water temperatures drops below 50oF. This is usually not a problem because bacteria and algae stop growing at this temperature. You can override this low temperature cutoff by switching to SUPER CHLORINATE for a day.
T,I live in Denton and have been using an ECG since June 2007. I pull it out early December due to the fact that the water is too cold for it to work. I install it typically the first 2 weeks in March because the water is warm enough (55+) to work reliably. My unit is a Pentair IC40. Works great. Last unit lasted 6 1/2 years. I acid wash 3 times/year and rarely have bubbles. Love it!