If you own a Keep Alive Bait Tank chances are you like the tank. I bought one during the winter and I enjoyed having a supply of live bait for my catfishing trips. It is the glow in the dark model and it is durable and easy to use. When hot weather came around I began to realize the limitations of the tank's design, particularly the filter system. If you are using the Keep Alive system (or any other bait tank) and you see scales circulating with your water you have one of the four problems with keeping shad alive. 1. scales, slime and debris 2. temperature to high 3. low oxygen 4. high ammonia and nitrates I float frozen bottles of water to adjust the temp. I also add salt to stimulate slime production and to harden their scales. Circulation and bubbles add oxygen. Water changes can keep ammonia and nitrates down. However, only a good filter will remove the scales and debris. So I decided to modify my Keep alive tank to address the problems of circulating scales and debris. First I ditched the two foam dough nuts around the bilge pump. I glued a 1/2" PVC elbow to the pump output and ran a length of 1/2" PVC pipe up through the top of the tank. At the top of the PVC pipe I installed a T fitting with two elbows to direct the water back down into the tank through two filter boxes. These filter boxes fit securely in square holes I cut in the top of my tank. I selected the plastic needle containers we use at the surgical center I work at for the filter boxes. Any plastic container with a rim or lip at the top will work as long as it fits in the small space at the back of the Keep Alive tank. If you are modifying a home made tank design accordingly. The old adage of "measure twice, cut once applies here. Once I was sure the filter boxes fit my holes I drilled nine holes in the bottom of each box. I cut a section of aluminum expanded metal used toi cover gutters to fit in the bottom of each box to make sure the filter medium does not stop up the holes. As far as filter medium, anything from an old sweat sock to Dacron pillow floss will work. As long as water passes through and it stops the scales and junk it will work. With my design I just pull out the dirty filter material and throw it away. Stick in some new filter material and you are off and running.