There should never be measurable ammonia in an established tank. That being said, it could be your test. I thought I had ammonia briefly (instant panic!) but then I tested some RO
water, and some tap water, and got the exact same reading for all three. So, it could be your test. Are you using API?
Nitrates however, are high. That might be ok in FO
, but for a Reef tank, I'd strive to get that lower.