Chris,

Next time you are at the grocery store, look at the liquid detergent refill bottles, like Tide, they would make great bottles also, and are pretty heavy duty......I've got a 300 oz (2.34 gallon) one here, that I am going to use on the next box I build, as it fits perfectly in the bottom and still leaves plenty of room. Also thinking about adding a 300 watt inverter, hell you never know when you will need a short burst of 120.......