Yep, I checked all that first thing. Source water measures zero ammonia, zero nitrires and about under 5 nitrates. I fed twice a day fine for months but this month I've cute it down a ton since I saw the level up, it happened pretty suddenly so I thought i killed the cycle on accident but its still not cycling but making its own nitrates fine? They get only either half a frozen food cube or a tiny pinch of bug bites once a day and its gone in under a few minutes. All fish accounted for, vacuumed every 3 days but nothing comes up really. I checked the mts and they seem alive and active. So I'm left thinking something is either messing with the cycle or remnants of the amguard messing with results or a bad test. I've put nothing in it but prime this week. Would ferts raise ammonia? I did start using nilocg this month instead of flourish but I'm dosing only a squirt once a week which is only half a dose for a 20 and weekly recommended amount was 2 to 3 times a week.With that stock in a planted tank you shouldn't have any ammona by the plants alone. A few guesses would be overfeeding or something(food maybe) somewhere decomposing. Another strong possibility is your tap water has ammonia in some form or another in it.
Lastly it could be a false positive, but i think that's less lilely than the other guesses.