I believe aquarium controllers are quite expensive and not as flexible as your own. This aquarium controller is developed by Pasquale D’Orsi who managed to manage and control most of controllable parameters in aquarium. Controller is based on PIC18F4520 microcontroller which is interfaced with various devices including: temperature sensor, 8 controllable relays, RTC, LCD, additional EEPROM memory, LED indicators and RS232.

Depending on time events that are scheduled precisely by using RTC module, and temperature readings, there can be various events triggered like switching heater, cooler, feeder, lights - you name it. Practically aquarium can be set to work autonomously for several days - so you don’t have to ask a neighbor to look after while you are somewhere on vacation Prototype project files can be downloaded here.