DIY Aauarium

DIY Aquarium

Water Changer

ramesh rajandran

This project was designed to make the cleaning process of an aquarium easier. Changing the aquarium water can take hours and it is not an easy task.

Two Solenoid Valves are used which work as Make Up and Draining Valves. The draining solenoid valve will energize when the pH level of the water is below the minimum level (5.8pH) or higher than the maximum level (7.8pH). The Turbidity Sensor will perform checks, and if the level is high the Drain Solenoid will energize to initiate the draining process.

Each and every move of this project is controlled by an EEPROM. It takes 23 minutes and 12 seconds to drain the water from a 9167 cm3 aquarium and 24 minutes and 53 seconds to replace the drained water.

The specially designed food-feeder box is made up of a 9 volt motor together with a gear to churn the food. A small hole is made on the box to allow the flow of the food into the aquarium. The automatic food feeder works on a 24-hour basis and also each time the make up process stops.

This project will ensure that the pH and turbidity of the water is well maintained. Besides this, it reduces the time spent maintaining the aquarium. With this design one can safely go on holiday for a few days without needing friends or neighbors to help feed the fish and clean the aquarium water.

What Aqua Kleen Does

Automatically drains the water
Automatically makes up the water
Controls the level of water in the aquarium
Displays the pH level of the water
Automatically controls the pH of the water
Feeds the fish at a predetermined time
Automatically controls the turbidity of the water

Common Problems Faced by Aquarium Caretakers

Difficulty in changing the aquarium water
Difficulty in maintaining the pH of the water in an aquarium
Difficulty in feeding the fish
Difficulty in controlling the turbidity of the water in an aquarium

What is Needed

An automatic control system to maintain proper living condition for fish in an aquarium. Any aquarium tends to build alkali level and get cloudy when water is not changed at the right time.
A system to control the alkalinity and cloudiness of the water. Existing systems clean water through a filter or recycle it. However upon filtering, only solid dirt can be removed.
An automatic food-feeding device that will feed the fish at a specific set time. Caretakers usually forget to feed their fish, which leads to hunger.

What Has Already Been Done

A search of books and the Internet was done. An automatic aquarium water changer was found. It works continuously and changes 5 gallons of water every hour. It

does not check for turbidity,
does not check for alkalinity,
wastes water.
Water filters work continuously filtering the aquarium water. They

do not check for turbidity,
do not check for alkalinity,
are unable to remove dirt particles dissolved in water,
waste electricity.


Stadelmann, Peter. (1991). 'Tropical Fish: Setting up and Taking Care of the Aquariums'. PP: 24-3
Scott, W. Peter. (1995). 'Complete Aquarium'. PP: 12-19
Schliwen, Ulrich. (1992). 'Aquariums: Expert Advice on Setting up and Planting a Tank and O'. PP: 25-32
Mills , Dick / Brown, Deni. (1996). '101 Essential Tips: Aquarium Fish'. PP: 1- 17

Designing and Testing Aqua Kleen Prototype
Building the Prototype

Solenoid valves are arranged and connected to a relay
Level switch is added onto the project.
Turbidity sensor and circuit board is prepared and fitted onto the project.
Wires and tubes are connected to specific parts to allow tasks to be performed accordingly.
Parts Involved

2 Solenoid Operated Valves
Level Switch
Turbidity Sensor and Circuit Board
Water tubes.

Tests were conducted when the turbidity level was high. The system responded as below without any errors.

Drain water
Reached low level - cut off
Make up water
Reached top level - cut off

Phase 1

Getting the Materials
Solenoid Valves and Level Switch are taken out of an old washing machine.
The two solenoid valves are used for draining and making up water. Whereas, the level switch is removed to control the level of water in the aquarium.
The solenoid valves and level switch are connected together with a relay to drain out water from the aquarium.
The level switch is connected with a tube to enable the air pressure to rush in.

Phase 2

Designing the Circuit and Sensor
A turbidity circuit board is designed together with a sensor compromising a LED together with a Light Dependent Resistor (LDR) fitted into a liquid paper bottle.
A pH sensor and also pH display unit is fitted onto a Perspex board.

Phase 3

A Programmable Logic Controller is used to control every action for specific conditions.
An automation program is used for programming the EEPROM.
Connections are made to the Programmable Logic Controller from each and every part of the project including the turbidity sensor and pH sensor, which is giving an output signal for automation.

Ramesh Rajandran displaying Aqua Kleen in the final competition at the International Science and Engineering Fair in Detroit, Michigan, May 2000.

Safety precautions are taken to ensure that the fish can live in the water, which is changed.
Expert consultants are interviewed to make sure that every connection are fitted and soldered properly to ensure no leakage occurs.