I think i've found the source of this ammonia. I tested for ammonia in my spare tank, it's a 200l tank that i use to make sea water for water changes. The test in the spare tank has 0.25 ammonia!!! how?? all it is, is a tank with a powerhead to mix the salt with the water and a heater, and the only chemical i use is a DE-chlorine chemical.
Also tested ammonia on the tap where i get the water from to put in the spare tank and it's on 0 ammonia.
Can sea-salt carry ammonia???? has anyone ever experienced this????