I just did an Ammonia test on my 20 gallon tank and it is showing 8.0 PPMS of Ammonia. The tank is cycled, and I have had fish in it for over a year, this has to be wrong, right? I'm using a Doc Wellfish ammonia test kit, but it's pretty old, could it be defective? I change the water once per week 25 percent. The tank is planted. I'm going to do a 50 percent water change right now. I'll be back.