Thanks Keith, \nI had thought long and hard about the bottom drain and thats also why I was looking at DrDave's Bio Filter, because it has the settlement area built in and would let the waste settle to the bottom of the filter where I could pump it out. Also why I was looking at pumps that could sit on the bottom and handle the waste. But I might lead towards the goldfish so I can have plants in it as well. \n\nDr Dave, \nHave you had anyone use your filter in a cold climate (I'm on the border of Zone 4-5)? I planned on using the rigid PVC to run into the filter and but connect it to the pump with the corrugated tubing. In winter I would disconnect the corrugated tubing, drain the filter, and use a compressor to blow out the rigid PVC lines so they wouldn't crack. Is there anything I have to do to preserve the beneficial bacteria in the filter? Any advice would be appreciated and I am going to go one winter without fish in it so I can experiment and find what works, for the filter and for keeping a hole in the ice.