Freshwater Ammonia0 ppm is the normal target for an established aquariumFreshwater Nitrite0 ppm is the normal target for an established aquariumFreshwater NitrateInterpret the trend against livestock, plants, source water, and maintenance historyFreshwater pHStability and species-appropriate conditions matter more than one universal valuePlanted NitrateBalance plant uptake, livestock load, fertilizer inputs, and water changesPlanted pHRead pH beside KH, CO₂ timing, aeration, and the livestock rangePlanted Carbonate hardness (KH)Use KH as buffering context, not as a stand-alone plant-health scorePlanted CO₂ contextEstimates from pH and KH are approximate and do not replace observationReef AlkalinityChoose a stable target appropriate to the reef and salt mix, then watch consumptionReef SalinityMany reef systems are maintained near natural seawater, around 35 ppt or 1.026 SG at 25°CReef NitrateInterpret nitrate with phosphate, coral response, feeding, export, and the system trendReef PhosphateInterpret phosphate with nitrate, feeding, export, algae, and coral response