Arduino Aquarium Controller

Features:

• 4x16 LCD display
• RTC module for timekeeping
• High power led lighting, with PWM ramp-up and ramp-down at set times.
• Mains relay for switching air pump on and off at set times.
• 12V solenoid valve for switching CO2 on and off at set times.
  • Solenoid driven at full power briefly to switch, then held at a lower current to reduce power consumption and avoid overheating the coil.

Schematic

The schematic can be copied & edited here