Yes, you can. Fill to the top of the rim. so about 75%. The fill/burp valve is readily available for about $10. (at tractor supply, Gemplers, mail order) You will need a pump unless you use just water, I used the cheap junky drill pump from Home Depot. There are dozens of threads on how to do this.. lemme know if you can't figure it out, and I will type it all out again.