DIY PVC Inline CO2 Reactor

Written by sarah freeman
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DIY PVC Inline CO2 Reactor
Mix CO2 into your aquarium's water with a homemade CO2 reactor. (Polka Dot Images/Polka Dot/Getty Images)

If you're trying to grow live plants in your fish tank, you might need to enrich the aquarium's water with additional CO2 to help the foliage grow. One way to mix more CO2 into the aquarium is through a CO2 reactor, which will dissolve the gas into the water before pumping it into the tank. While you can buy a CO2 reactor from the store, you can also save money by building one at home.

Skill level:
Moderately Easy

Things you need

  • 15-inch long 2-inch wide PVC pipe
  • 2-inch coupling slip (2)
  • PVC solvent glue
  • 2-inch reducer bushing, with half-inch threaded port (2)
  • Half-inch barb (2)
  • Thread seal tape
  • Drill
  • Airline connector
  • Waterproof resin glue
  • Scissors

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  1. 1

    Glue the couplers onto either end of the PVC pipe. Secure them so that only half of each coupler is over the end of the pipe.

  2. 2

    Attach the reducer bushings into the couplers by placing each one inside the couplers. Ensure that the threaded port of the reducer bushing is facing out. Glue them in place.

  3. 3

    Wrap thread seal tape, also known as Teflon or plumber's tape, around the threads of the barbs. This will create a waterproof seal when the barbs are placed in the reducer bushings.

  4. 4

    Thread the taped barbs into the reducer bushings. The barbs will make the connection for the CO2 reactor to the aquarium's intake and exhaust hoses.

  5. 5

    Drill a hole into the body of the CO2 reactor. This should be placed near the bottom of the reactor without interfering with the attached couplers. This hole should be large enough to snugly fit the air line connector.

  6. 6

    Use a waterproof resin glue to secure the air line connector to the drilled hole. Do not to glue over the opening of the air line connector.

  7. 7

    Turn off the aquarium's pump to hook up the CO2 reactor. Snip the pump's hose in half. Attach one end to the top reactor barb to become the intake hose, and secure the other end to the bottom barb to become the exhaust hose. Secure both in place using a hose clamp.

  8. 8

    Connect an air line hose into the air line connector affixed to the body of the CO2 reactor. Ensure it has a tight fitting. Attach the hose to the CO2 source, which might be a CO2 tank.

  9. 9

    Turn on the aquarium's pump and the CO2 source. The aquarium's water will now be pushed through the CO2 reactor, be enriched with CO2 and flow out the other end into your fish tank.

Tips and warnings

  • Use a check valve in between the CO2 reactor and the CO2 source, which will prevent water from back-flowing.

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