Ammonia Levels wont go down

[amit.rajaram]

I started my first tank 7 weeks ago, and diligently researched and followed all advice. I have 4 guppies, 2 platys and a recently added Gourami. All are doing well. They are extremely active and are eating well, and the water is clear. However, my Ammonia reading still shows 0.2ppm (Nitrite is 0 and Nitrate is 10ppm). I am using the API master test kit and am following instructions to the last word. I do 20% water change weekly and vaccuum the gravel at the same time. Why is my Ammonia not falling?

There is no way of knowing how much of the reading is the toxic Ammonia vs the harmless, so I'm adding a quarter capful of Prime every other day just to be sure.

 

[Mebbid]

If you're changing only 20% water per week I would expect to see a higher level of ammonia or nitrite if the tank isn't cycled.

How large of a tank is this?
Have you tested your tap for Nitrate?

 

[amit.rajaram]

Its a 36g tank. I change about 7g every Sunday. I haven't tested tap water at all, thats a great idea. I will do that. Will Nitrate in tap water account for higher ammonia, because for a tank thats cycling for about 7 weeks, the Nitrite at 0, and Nitrates at 10ppm, seem to be acceptable values. Is it normal to only have Ammonia levels out of whack? I'm just wondering if I'm doing anything wrong.