My tap water is .25 sometimes close to .50 ammonia.After a 25% water change the ammonia is nowhere to be found.The cycle converts(eats) it instantly and the tank water will read zero ammonia.
I'm sure your local water supplier is using chloramines to treat the water. This is a compound of chlorine and ammonia. When you treat for chlorine, it breaks the bond and you're left with ammonia. Treatments like Prime and some others bind the ammonia, changing it into ammonium which is relatively harmless, but still available to your nitrifying bacteria.
Some test kits will pick up on this ammonium and give you a "false" reading... At least for our purposes. As far as the test kit is concerned, there's still ammonia in the tank, but the fishes just don't notice it.
It seems that you have an established tank, so any ammonia you might introduce via water changes should be taken care of by your tank in short order.
That's the tricky thing about water departments and chloramine. They can switch from straight chlorine to chloramine *at any time* and they don't have to give warning.
I currently live in a city that just uses chlorine, but I'm going to treat with Prime anyway because there may come a day when they'll switch and I won't know it.
I think you'll find that the vast majority of people here just fill their tanks with plain old tap water. There's nothing wrong with it, even if the water company uses chloramines. Chloramines are used to keep the water safe to drink on the way to your house.
As long as you treat for the water chemicals, you'll have no issues. Buying bottled water is prohibitively expensive and unless you're going for a specific type of water, like rift lake cichlids, you don't need to go to that extreme.
My tap water is rated for Ammo @ 0.5 - 0.75. So what you're telling me is that if I just put tap water (with this Ammo rating) and treat the water (with AmQuel+ which helps neutralize the Ammonia, Nitrites, Nitrates, etc) then the Ammonia will eventually cycle out? I would hate to put tap water and then the ammonia never leaves.
I'll try that next time. The last water change read the ammonia level at 0.25 after two hours. I got concerned at the reading and did another water change with drinking water to be safe. I'll try that next time.