How to Build a DIY Central Air System for Your Aquarium Fish Room

Owning a fish room full of aquariums is the dream of many fish keepers. However, it can be hard to find exact instructions on how to build one since everything is so customizable and cannot be purchased ready-made from the store. One of the main milestones of setting up the fish room is installing a central air system. Rather than plugging in an individual hang-on-back or other filter for each fish tank, many veteran aquarists use a linear piston air pump that can supply air to multiple sponge filters (or other air-driven devices) for the entire fish room. Linear piston air pumps are great for fish rooms because they’re economical, energy efficient, reliable, and nearly maintenance-free. Plus, they are much quieter than diaphragm pumps and blowers that output the same amount of air.

How powerful of a linear piston air pump should you get? This is very difficult to estimate since the amount of air pressure needed for each tank varies depends on the tank size, depth, resistance of the connected device, and other factors. We use the LPH45 linear piston air pumps in the Aquarium Co-Op retail store and our personal fish rooms at home, and it outputs 47 liters of air per minute. Our rough estimate is that 1 liter of air per minute can run 1 air stone, so the LPH45 can handle approximately 47 tanks. Obviously, it will handle fewer tanks if all of your aquariums hold 300 gallons each, and it will handle more tanks if you only have 5-gallon aquariums. The great thing about linear piston air pumps is that they can be used in series, so if you find you need more air or you decide to expand your fish room later down the road, you can add another linear piston air pump to the central air system to get an added boost.

LPH45 linear piston air pump

How to Install a Linear Piston Air Pump in a Fish Room

The overall concept is to create a loop of PVC pipe along the perimeter of the room that starts and ends at the linear piston air pump. This will carry air to all your tanks that are set up against the room walls. In this example, we will be mounting the PVC loop high up on the wall closest to the ceiling so that check valves are not needed for each sponge filter or air-driven device. However, if you prefer to mount the PVC loop on the ground instead, alter the instructions accordingly.

Materials

• LPH45 linear piston air pump
• 1” PVC pipe (enough to complete the perimeter of the room and a little extra to reach the air pump)
  • ¾” PVC pipe can also be used, but nothing smaller or else it can’t handle the air volume. If you choose a different diameter than 1”, make sure to adjust the instructions accordingly.
  • You can use PVC pipe with thinner walls (not Schedule 40 or 80) since it is just handling air, but it may warp a little when cutting it.
• 1” PVC elbow fittings for each corner of the room
  • Get the appropriate angle for the elbows, depending on the shape of your room.
• 1” PVC couplings
  • If the PVC pipe isn’t long enough to reach the entire length of a wall, use a coupling to connect two PVC pipes together.
• 1” PVC tee fitting (for connecting to the air pump)
• PVC pipe adapter with 1” slip fitting x ¾” female threaded adapter fitting
• PVC barbed hose adapter with ¾” hose barb fitting x ¾” male threaded adapter fitting (to fit onto the ¾” viny tubing)
• ¾” vinyl tubing (to connect the air pump to the PVC loop)
• Two hose clamps (that can tighten around the ¾” vinyl tubing using a screw)
• Clear PVC cement or glue
• Airline tubing (to connect the PVC loop to each aquarium)
• Metal air valves (to mount into the PVC loop)
• Plastic inline air valves (to fine tune the air pressure for each tank)
• 1” conduit straps (to mount the pipe to the wall) with matching screws
• PVC pipe cutter (that is big enough to cut 1” pipe)
• Electric drill with 3/16” drill bit (to fit the Aquarium Co-Op metal air valves)
• Sharpie marker
• Stud finder (optional)

Instructions

1. Place the linear piston air pump on a solid surface in the fish room that is near a wall, is tucked out of the way, and won’t be too loud if it vibrates. It should also have access to free-flowing air, not shut away in an airtight area. Putting a piece of foam or yoga mat underneath the air pump can help dampen the vibrations. For the lowest sound levels, you can also mount the pump remotely in a non-airtight cabinet or another room like the garage.

Steps #2-3 A scaled-down version of a PVC loop with a tee fitting

2. Build a loop of PVC pipe that follows the entire perimeter of the room. If the room is rectangular, then build a simple rectangular loop out of PVC, connecting the pipes using a 90-degree elbow fitting at each corner. If the room has a different shape, customize the shape of the PVC loop using elbow fittings with the correct angles.
3. Locate the section of the PVC pipe loop where the air pump will be closest to. Cut the PVC pipe loop right above the air pump and insert the PVC tee fitting in line with the PVC pipe loop. (The tee fitting should have the horizontal section on top and the vertical section pointed downward, so it looks like a capital letter ‘T’. The PVC loop connects to the horizontal section of the tee fitting.)
4. Test fit the PVC loop to ensure that it matches the perimeter of the room before gluing the pieces together. Once you glue the PVC together, they’re permanently connected and you won’t be able to change anything without cutting out the PVC pipe.

Step #5 Apply a layer of PVC cement inside the fitting and outside the PVC pipe.

5. Start in a corner of the room and glue the PVC pipe to the elbow fitting. Mount this PVC section to the wall near the ceiling by screwing in a conduit strap wherever there is a stud in the wall. (Use a stud finder if needed.)
   1. Wipe the outside of the pipe end and the inside of the fitting to remove excess dust or particles, and then apply a layer of glue to these two surfaces. There is no need to use too much glue, so just apply enough for there to be a continuous layer.
   2. Firmly push the pipe into the fitting as far as it can go, and then turn the fitting a few times to ensure the glue spreads all around the pipe. The PVC glue should set in a minute or two.

Step #6 Glue and mount the PVC loop piece by piece into the wall studs.

6. Continue attaching and gluing one additional PVC pipe at a time, and secure it to the wall with a conduit strap wherever there is a stud in the wall. The last piece should complete the PVC loop.

Step #7 Connect the PVC tee fitting to the vinyl tubing, which leads to the air pump.

7. Cut a length of PVC pipe that will connect to the vertical section of the tee fitting and is long enough to reach the air pump down below. After gluing it in place, add the PVC pipe adapter (1” slip fitting x ¾” female threaded fitting) to the end of this vertical length of PVC pipe. Then screw the PVC barbed hose adapter to the end of the PVC pipe adaptor.

Step #8 Connect the ¾” tubing directly to the air pump with a hose clamp, and add foam underneath the air pump to dampen the noise.

8. Connect one end of the ¾” vinyl tubing to the PVC barbed hose adapter, and connect the other end directly to the air pump. Tighten a screw-type hose clamp around each end of the vinyl tubing to prevent air leaks and accidental disconnection.
   1. There are many techniques for connecting the air pump to the PVC loop, but with this method, you will not be using the 90-degree black rubber tube and two squeeze-type hose clamps that come with the LPH45 air pump.
9. Use the Sharpie marker to mark each location on the PVC pipe loop where you have an aquarium nearby that needs an air source. Using the electric drill with the 3/16” drill bit, slowly and carefully drill a hole in the PVC pipe in each marked location so that the holes are angled downward towards the aquarium. You can drill a few extra holes in case you plan on expanding the number of aquariums someday in the future.

Step #10 Use the electric drill to screw the metal air valve into the PVC loop.

10. To insert the metal air valves, remove the drill bit on the drill and insert a metal air valve into the chuck so that the shorter end of the valve is pointed away from the drill. Using the electric drill, slowly screw the valve into one of the holes in the PVC pipe so that the threads bite into drilled hole. Once the valve is close to being all the way seated, loosen the chuck, remove the valve from the drill, and finish hand-tightening the valve to its final position.

Step #11 The left air valve is in use, so it’s fully open and connected to airline tubing. The right air valve is not in use, so it’s fully closed.

11. Connect airline tubing from each of the metal air valves to the sponge filter or other air-driven devices inside the aquarium. Fully open all of the metal air valves so that maximum flow reaches the tanks.
    1. Because the PVC loop is above the aquarium, check valves are not needed. However, if you mounted the PVC loop below the top rim of the aquariums, check valves are needed for each air-driven device to prevent water from siphoning out of the aquarium during a power outage.
    2. If you drilled extra holes and metal air valves into the PVC loop that are currently not in use, fully close the unused air valves until they are needed.
12. Because it is hard to reach the metal air valves near the ceiling, we like to install a plastic air valve between the metal air valve and the sponge filter (or air-driven device). The plastic air valve should be outside the fish tank but near the top aquarium rim. Once the air pump is turned on, you can easily adjust each plastic air valve to customize how much air you want going into each aquarium.

Tips and Tricks

If you only have 10-15 aquariums, you may not have enough air coming out of the PVC loop, so you’ll need to bleed off some air. Drill a few more holes into the PVC loop, attach a metal air valve to each hole, connect a short length of airline tubing to the air valve, and connect an air stone at the end of the airline tubing. (The air stone should not be inside water.) This will lessen the noise while bleeding out excess air.

If you have more than 20 aquariums, the LPH45 air pump should be adequate, depending on how much air goes into each device. (As mentioned previously, the number of outlets, tank sizes, and depth of each tank will all determine how much air is being used.) If you find that the air pressure is too low in certain tanks, you may need to add another linear piston air pump to the PVC loop. Insert another PVC tee fitting (Step 3) near the location of the second air pump. Then follow Steps 7-8 to connect the air pump to the PVC loop. Afterwards, you will need to readjust the plastic air valves on each tank to fine tune the air pressure.

A central air system is not the most attractive method of filtration, so some hobbyists install hooks above the PVC loop and hang fabric curtains on them. The curtains hang slightly in front of the PVC loop and hide the many lines of airline tubing dropping down from the ceiling. You can still easily access the PVC loop and metal valves by unhooking the curtains.

Finally, set a calendar reminder to check the air filter on the air pump at least once a year. A linear piston air pump requires very little maintenance, but over time, the air filter can become clogged with dust, pet hair, and other contaminants. If the air filter is full of debris and no longer intakes enough air for the system, it only takes two minutes to install a replacement air filter to ensure that your fish room filtration continues working properly.

For more information on how to build a fish room, visit the Fish Room Builds section of our Advice Center to see how we set up fish tank racks, an automatic water change system, and more.