I actually didn't add those, the previous owner had them in case he added reactors. lol

Cliff, the feeding tube is very easy. Basically, you add a piece of PVC with a 90 degree elbow at the end, and a screw in cap. You drop the food in the tube, screw the cap on good, and then open the valve. The food is sucked into the water stream and into the tank. It's a bit of overkill for this size setup (really useful for those monster tanks that you need a step ladder to reach the top) but it is a nice option for frozen foods. It distributes the food really nicely so that all the tank inhabitants have an equal chance at the food.