Ammonia out burst -- Help me!!!

[Relaxedguy06]

I have a 36-gallon bowfront aquarium. It's been established now for nearly a year. It currently only has 1 Angelfish, 2 Sunburst Platys, 2 Albino Cory, and 2 Otolincus. I keep it clean and perform weekly maintenance but lately, I'm having trouble with ammonia build up. I've been doing tests and the water is showing dangerously high ammonia levels.

So far I have:
Performed a 50% water change
Completely vacuumed out the tank
Used API Ammo Lock

Waited a couple of days and I was still getting high levels so I did it all again.

Am I missing something????

 

[libertybelle]

How big is the angel? How much are you feeding? What is your substrate? Live plants, and if so are they healthy? Have you tested your tap water? Oh and what is dangerously high and how are you testing it. Have you tested nitrites and nitrates?

 

[CardinalDiscus]

How long have you had your test kit and what test kit is it check to see if your fishes gills are red. If there all fine it might be just and old test kit. If not feed smaller amounts and perform 30% water changes daily. If it is your lants rotting dying then get them out imediatly. Hope this helps best of luck going your way.