Rainbow HC-3315 High Capacity Off-Line Swimming Pool Feeder RA3315Rainbow HC 3315 High Capacity Off Line Swimming Pool Feeder for Chlorine or Bromine RA3315. The efficient, easy way to sanitise your pool or spa The Rainbow Models 300 and 320 feeders not only save time, but also reduce manual handling of chemicals. They use large or small chlorine or Bromine slow dissolving tablets to make sanitising your new or existing pool or spa easy and automatic. Both install easily on the pressure side of the pump, downstream