Posted by @Chris_Lewis · 14h ago
The liquid master kit is the single best tool a freshwater keeper owns, but the colors trip everyone up at first. Here's how to read each one.
Ammonia (NH₃/NH₄). Bright yellow = 0 ppm, which is what you want. Any shift toward green means ammonia is present and your fish are being harmed — green is an emergency, time for a water change.
Nitrite (NO₂). Sky blue = 0 ppm (good). Anything toward purple means nitrite is present and toxic — common during cycling, dangerous with fish in the tank.
Nitrate (NO₃). Yellow/light = low (good). Orange to deep red = high; that's the cue for a water change. The #1 nitrate testing error: not shaking reagent bottle #2 hard enough. Bang it on the table and shake it for a full 30 seconds, then shake the tube for another minute, or you'll get a false low reading.
pH. The regular pH chart tops out around 7.6; if your water reads maxed out, use the High Range pH bottle. Don't chase a "perfect" pH — a stable pH your fish have adjusted to beats a number you're constantly fighting.
Tips that make readings reliable: test against a white background in good daylight, hold the chart right behind the tube, and rinse tubes between tests. Read at the time the instructions say — colors keep developing.
Not sure what's safe for a given fish? Their species database page lists the parameter range they actually want.
Your turn: post a photo of a reading you're unsure about (against white, good light) and we'll help you call it.