5 Colo. Code Regs. § 1003-5-3.11
All chemical feeders shall comply in all respects with the standards of the NSF covering such equipment. Feeders shall be of sturdy construction and materials which will withstand wear, corrosion or attack by the solutions being fed. Feeders shall have a graduated and clearly marked dosage adjustment to provide flows from full capacity to 25 percent of such capacity. The device shall be capable of continuous delivery within 10 percent of the dosage at any setting and shall be capable of supplying dosages at the rates needed to provide the residuals required by these regulations and standards. The feeder shall incorporate failure proof features, so the chemicals/disinfectant cannot feed directly into the pool, water supply or the pool enclosure under any type of failure of the equipment or its maintenance. The feeder shall be capable of supplying at least the minimum equivalent of one (1) pound of chlorine per twenty-four (24) hours for each ten thousand (10,000) gallons of pool capacity under conditions of maximum load. All chemicals shall be introduced downstream from the heater.
Owners applying chemicals for controlling pH through chemical feed equipment shall provide equipment with:
5 CCR 1003-5-3.11