Ammonia Dead Spot In Tank?

Alright I have the weirdest thing happening in my 55 gallon freshwater community tank. I use the apI freshwater master kit and I keep getting different ammonia readings. I thought maybe it was the test bottles so I bought a new set but the problem persists. The weird thing is when I get my water for testing from one spot in the tank the ammonia is off the chart but if I test from anywhere else it's zero. I've had the tank running for about a month with previously cycled media and have had zero fish losses. Is it possible there's a dead spot with tons of ammonia? I have two hobs and one sponge filter so it's hard to believe the agitation is low enough to cause this. I'm stumped

 

I've never heard that before. Are you sure you're rinsing the tubes really well before each test? There could be some residue from the solutions that are causing faulty results? I usually rinse mine in warm water really well and make sure they are completely dry before using them again.

 

I have never heard of this before. Wonder if anyone else has..

I know you don’t test, but maybe some insight?

 

I could see maybe a test residue causing it. I let them air dry and rinse them after every use. But still, I might not be doing a good enough job. But I can't get over how it only works if I grab the water to test from one spot. I think next I'm going to try each of my tubes by just testing the ammonia in all 4.

 

I know that in the wild, one of the skills an Apistogramma or Pelvicachromis dwarf cichlid parent is known to have is the ability to sense water quality and keep fry away from bad spots. So they can exist, and I have read of fry guarding Cichlid parents keeping the fry away from spots in the tank.
I don't know of water test results from those spots, but if food accumulates, a snail dies under the gravel, etc, it makes sense there would be higher ammonia spots.