When you feed your fish, the food usually floats on the water surface where it spreads and disperses but any food that is not found or eaten immediately, will disappear into the decorations and filter where it will slowly decay and contaminate the water. The difference with the EHEIM feedingSTATION is that the food delivery is controlled from the food chamber - underwater. The fish are already waiting and the food cant drift very far - everything is eaten and the water will stay cleaner for longer. An additional benefit is that you can observe and monitor your fish at the feeding station.