No, we do not recommend purchasing a larger water tank. Our CT and HB models come with a One Gallon Tank. Our T-Series models come with a Five Gallon Tank. Both of these tanks utilize different filters and hose lines that may not be compatible across different models. We do offer a float valve combination in the Five Gallon Tank that can be used for the T-Series incubators. This will enable you to hook up a water source to the tank for continuous flow. You will have to be mindful of water pressure from the existing water source.