Will this size work for a aquaclear 50 filter?

I believe that our bags are little longer. That shouldn't be a problem in terms of it working properly in the Aquaclear 50 filter. Simply fill bag with your desired amount of carbon, and then pull the drawstring tight to cinch the top. Next, fold over the top of the bag until it is at the desired height, and wrap the drawstring around the folded top of the bag. Once all the string is wrapped around the bag tie it off. Use a knot that can be easily untied, because these mesh bags can be reused many times!