Why does Modern Reef AmmoMix show zero ammonia with Salifert test

Question

Hi everyone,

I'm cycling a new tank (approx. 80 L, started Friday) and dosed 70 drops of Modern Reef AmmoMix today (1 drop per liter as per instructions). I measured 45 minutes later with a Salifert NH4 test and it still shows 0, no color change at all.

Setup: Tropic Marin Bio-Actif salt, CaribSea Fiji Pink live sand, ARKA dry rock, TM NitriBiotic dosed on Friday.

Shouldn't 1 drop per liter show at least something? Is the Salifert test not sensitive enough at this level, or could the kit be faulty? Has anyone had the same experience with AmmoMix?

Thanks!