I would definitely say that has to be a false positive. There's no way you could have this long of a spike in ammo (what, a couple of weeks now?) without also having some movement of nitrIte levels.
The fact that your tap water registers .25 of ammo - and only after you treat it - confirms this.
So, your thread question should be "does anyone else have chlorAMine treated tap water? Do you guys get false positive ammonia readings after dechlorAMinating with Prime/Stress Coat?"
It is worth mentioning, and I'm sure you know this already, that now you may indeed see real spikes in ammo/nitrite/nitrate, in that order, until your bio filtration has time to catch up to your new increased bio load (adding the ray). So don't slack off on water testing/changing now. I would treat anything above .25 ammo as >0, and do WC accordingly.
The fact that your tap water registers .25 of ammo - and only after you treat it - confirms this.
So, your thread question should be "does anyone else have chlorAMine treated tap water? Do you guys get false positive ammonia readings after dechlorAMinating with Prime/Stress Coat?"
It is worth mentioning, and I'm sure you know this already, that now you may indeed see real spikes in ammo/nitrite/nitrate, in that order, until your bio filtration has time to catch up to your new increased bio load (adding the ray). So don't slack off on water testing/changing now. I would treat anything above .25 ammo as >0, and do WC accordingly.