Blackwater Cool Season, 5 lb bag, Medium Pellet Beneficial Bacteria 2" Bulkhead fitting

2" Bulkhead fitting

The pressure relief valve protects the compressor from excessive  backpressure if there is some sort of blockage in the airline or diffuser

Photo shows brown color

3 fountain nozzles

Blackwater Cool Season, 5 lb bag, Medium Pellet Beneficial Bacteria 2" Bulkhead fittingThis terrific line of Blackwater Koi Pellets gives you the quality and variety of high end Koi Feeds at the price of a standard staple diet. All varieties come in a vacuum packed resealable zipper lock bag. Cool Season This is a highly digestible diet formulated for Koi and Goldfish when water temperatures are consistently below 60 degrees F.