Marine Color Sunsun HW 3000 aquarium inlet and outlet review 

I purchased them from Walmart. They can fit up to a 40 breeder. You just have to cut some wood to fit on top of the steal shelving to make it smooth. WORKPRO 48-Inch W x 24-Inch D x 72-Inch H 5-Shelf Freestanding Shelves, 4000 lbs. Capacity, Adult

I have no experience with the HW304b. I would have to assume this would work with their own products. It looks like the hose diameter would be the same.