Aquarium Automatic Water Change System

The biggest complaint I have always had about keeping an aquarium is changing the water. I must confess that there was time when I didn’t believe in changing the water very often, I would change the water once every few months. The tank looked fine and the fish seemed happy. Then one day I bought some water tests and tested the water. The nitrates test was off the chart dark red. Anyway, I have since changed my ways and now I do regular water changes, but it’s automated. My automatic water change system does 20% water changes every day, it does 5% at a time, four times throughout the day. The old water is them pumped out to water my garden in the back yard. The aquarium is on an exterior wall of my house. The sprinkler valve box is just on the other side of the wall. We recently built this house, and so I did the landscaping with the aquarium in mind. I have a sprinkler valve just for the aquarium.

Water is supplied through my sprinkler system. The sprinkler valve box is on the other side of the wall from the aquarium. The aquarium has its own sprinkler valve. The sprinkler is programmed to come on 4 times per day at 3:00 AM, 9:00 AM, 3:00 PM and 9:00 PM for 15 minutes each time. This equates to approximately 30 gallons per day.

I have a pressure regulator attached to the sprinkler valve, and then a carbon filter to remove chlorine and other contaminants. The filter connects to a hose. I have adapters to get from the filter to ¼” drip tubing.

I used bulkhead fittings to go through the wall. The cord coming out just below the fitting is for the water pump. The two lower cords are for the water level sensor and the sprinkler control wire.

The tubing then goes through a ¾” PVC pipe that goes through the wall and up to the aquarium. This pipe transitions to 1” inner diameter tubing inside the house and up to a bulkhead fitting to the aquarium. This also serves as an emergency drain should the main over flow drain become blocked.

The tubing then comes up and empties into the top of the aquarium.

Water then fills the aquarium and overflows through the main drain.

The supply and drain bulkhead fittings are setup using black PVC fittings and pipe. These fittings are for PVC furniture, but they work great in the aquarium.

The drain goes through a bulkhead fitting, through a tube to a PVC pipe that goes through the wall and empties into the water barrel on the other side of the wall.

The aquarium line is on the bottom, and the sprinkler line is on top. The two fat fittings are check valves

There is a 1/3 HP pump with a float valve. Once a day the pump is activated for 5 minutes (it takes about 2-3 minutes to empty the entire barrel) pumping the water out to the garden to water the plants. The garden is plumbed for both aquarium water and tap water using check valves to prevent back flow.

The sensor is on the far wall to the right of the black cords

There is also a water level sensor in the barrel, if the water reaches the sensor the pump will kick on and lower the water level. A text message is sent indicating the high water level, encase the pump has failed.

The automation is done through the Apex Jr. I originally tried to use the 24DC output from the Fluid Monitoring Module to control the  water supply valve, but ran into problems. I currently use a 24 volt AC adapter plugged into an APEX Jr. controlled outlet to control the water supply valve. The pump out to the garden is also controlled by the APEX Jr.

I have been using the water change system for about three months now and it works very well. The water enters at a pace that the temperature difference between the aquarium and water supply is not an issue. The water changes happen almost unnoticed, it’s not any louder than the normal water flow. You can see the stream of water and bubbles at the top of the aquarium. Which I like to see to know that it is working. I do have to vacuum decaying plant matter, brown algae, and other junk off the bottom occasionally, but I usually only remove about 10 gallons. I just manually turn the supply water on for 20 minutes and the water is replaced. I then dump the water that I remove into the water barrel outside. To be pumped to garden the next day. If I put enough water in the barrel to reach the water sensor, the pump will kick on automatically. I have it set to turn on for at least 30 seconds, which is long enough to lower the water level well below the sensor, but not empty the entire barrel.