Tank cycle

I have a new 40 gal breeder tank with 3 fish in it. I stared out with a minimal amount of ammonia since Hampton va water has ammonia added...ewww! My ammonia reading in the tank is going down but no nitride is being produced, how can this be???? I started the tank 3 days ago and expected more ammonia being produced be now! My tank is planted with real plants. Brown algae is showing on my decoration only. I keep a bright light on for 8 hours a day.
I really need heip, thanks!

sounds like it is actually cycling well. no need to worry, dont look for problems where there are none