Sorry i just need a clarification, your tap water is showing ammonia present aswell as your aquariums?? I know that the ammonia gets detoxified when it is conditioned, but i would assume that the beneficial bacteria would clean that up. Normally Ammonia should be 0 in the tank, because its usually very toxic, You should have 0 Nitrites showing as-well. Nitrate isn't concerning because its not really as toxic as the other two. What kind of test kit are you using?? I find test strips to be very very bad.
OFF TOPIC this is the video i mentioned. It is a guy yelling at his dog named Fenton thats chasing deer in a park in england. http://www.youtube.com/watch?v=3GRSbr0EYYU
Edit: I noticed that your readings are Ammonia: 0.25 Nitrite: 0 Nitrate: 20 (ish)
Usually a tank that hasn't cycled would show ammonia and nitrite readings but this doesn't seem to be the case. Maybe you just need more filtration. Your tank is very large but maybe your filter isn't picking up the left over poo from your fish. Also what kind of media do you have in your sump??