Probe Readings
1
Measures acidity/alkalinity of the water. Optimal range for aquaponics is 6.4–7.2 pH. Affected by nitrification (lowers pH) and photosynthesis (raises pH).
Dissolved oxygen available to fish and bacteria. Should stay above 5.5 mg/L. Drops at night (no photosynthesis) and in warm water (lower O₂ solubility).
Oxidation-Reduction Potential indicates water cleanliness. 250–400 mV is healthy. Low ORP suggests organic buildup; correlates with DO.
Electrical conductivity reflects dissolved nutrient concentration. 300–1500 µS/cm is typical. Rising EC means nutrient accumulation; drops after water changes.