And not to sound like a broken record, but yu need to feed or apply the food from the tube side of the crwon, as thats the side of ther crown that mainly gathers particulate food. If you look at a FD thats been there and fed, yu wil see it expell waste out the open end....All I do is allow particulate matter from frozen foods to filter around it with a power head providing flow. Its more natural way of them feeding, and in no time its easy to see them pull the crown inside the tube during feeding,and then extend it again and then pull it in as its filtering out particulate matter in a more natural way.