Good job but it is a big tank considering the size and the small amount of feeders, I would recommend a much smaller tank, otherwise not only will it take a long time to euthanize the rat but you will go through a lot of CO2, I use a 7 quarts tub it allows me to do 3 retired breeder rat at the time, 20/25 mice or rat pups in no time and with less CO2, I do have a 5 lbs CO2 cylinder with a regulating gauge as well.