Nutrient Solution Management

Monitor pH, EC/TDS, and water temperature for optimal plant nutrient uptake.

Sensors

Monitoring nutrient solution.

pH Monitoring

pH determines nutrient availability. Most plants absorb nutrients best between pH 5.5-6.5.

Sensor Types

  • Analog pH probes - Generic probes with Adafruit/Atlas circuit
  • Atlas Scientific - I2C pH sensors with automatic calibration

Connect to A0-A3 pins with analogRead() in Arduino.

EC / TDS

Electrical Conductivity measures total dissolved solids - how much fertilizer is in your solution.

Typical Ranges

Seedlings 400-600 ppm
Vegetative 800-1200 ppm
Flowering 1000-1600 ppm

Water Temperature

Root zone temperature affects oxygen solubility and root health.

Ideal Range

  • Optimal: 65-70°F (18-21°C)
  • Acceptable: 60-75°F (15-24°C)
  • Too warm: >75°F - root rot risk
  • Too cold: <60°F - nutrient lockout
Calibration

Calibrating pH and EC sensors.

pH Calibration

Two-point calibration using buffer solutions:

  1. Rinse probe with distilled water
  2. Immerse in pH 7.0 buffer, adjust offset
  3. Rinse, immerse in pH 4.0 or 10.0 buffer
  4. Adjust gain/slope until reading matches
  5. Store probe in storage solution

Recalibrate weekly or when readings seem inaccurate.

pH Calibration
// Raw sensor reading
int sensorValue = analogRead(A0);

// Convert to voltage
float voltage = sensorValue * (5.0 / 1023.0);

// Apply offset and gain (calibrated)
float pH = voltage * 3.0 + 7.0;

// Auto-compensate for temperature
pH = pH + (0.03 * (25.0 - waterTemp));
Automated Dosing

Automated pH control.

hydroMazing can automatically add pH up or pH down solution to maintain optimal levels:

pH Control Logic

pH Control Algorithm
// If pH too low (acidic), add pH up (base)
if (ph < 5.5) {
activate(PH_UP_PUMP);
// Pulse for calibrated duration
delay(PH_UP_DURATION);
deactivate(PH_UP_PUMP);
}
// If pH too high (alkaline), add pH down (acid)
if (ph > 6.5) {
activate(PH_DOWN_PUMP);
delay(PH_DOWN_DURATION);
deactivate(PH_DOWN_PUMP);
}

Always add acid to water (never water to acid), and wait 15-30 minutes after adding before retesting.

Hardware for Dosing

💧

Peristaltic Pumps

Best for precise liquid dosing. Control via MOSFET or relay.

⚡

Solenoid Valves

Fast opening/closing for gravity-fed systems.