How to Build an Aquarium Plumbing Manifold

As it pertains to an aquarium, a manifold creates branches of your main return line to not only supply water to your display, but also feed water into reactors, UV sterilizers, and other applicable aquarium equipment using a single pump. They can come in handy because you won't need multiple small feed pumps submersed or plumbed into your sump and can help keep things tidy under the tank.

The most common use for a manifold is to feed water into a fluidized media reactor because this is such a common piece of equipment but it also can work great for feeding a UV, calcium reactor, turf scrubber, macroalgae reactor, and pretty much anything that needs a water feed from your aquarium. Each branch of the manifold can be adjusted to suit various pipe diameters and flow is controlled using a ball valve. 

A single manifold will have the primary return line plus one branch for connection with a piece of equipment, a dual manifold has two branches for connection with two separate pieces of equipment, and so on. The number of branches in your manifold can vary but most tanks will have no more than three, typically only one or two are all that you need.  You don't have to have an immediate plan for all of the connections on your manifold because you can just as easily close off the connection for use down the road. It's sometimes just better to have the manifold, even if you're not using it right away.

How to Build a Manifold

Assembling a manifold is fairly easy with readily available PVC plumbing parts and we also sell a pre-assembled manifold with two 1/2" water lines which can make things easy for those of you who may not be confident in your plumbing skills. Either way, installing the manifold is best done when building your aquarium but can also be installed after the fact as long as you have the space.

Keep in a mind a manifold will add head pressure to your return pump slowing down the flow.  Keep this in mind when choosing a pump and be sure your pump is strong enough to supply not only your return flow but also the water flow required for your various pieces of equipment that will be attached to the manifold.  

Always match the primary plumbing diameter to your return pump and do not reduce the plumbing diameter until after your manifold Tee. Reducing plumbing diameter before it's necessary just puts more pressure on the pump.  Also, always use ball valves that have union connections so you can remove the valve for cleaning.

Single Manifold

The following instructions are intended for installing a 1/2" single manifold into an existing 1" PVC return line but the same steps can really be applied to building a manifold into any system.  Adjust the pipe diameters to suit your particular system and if you want more than one branch, install two tee fittings instead of one. Generally, the tee fittings are located side by side but they can technically be installed anywhere on your return line that makes sense to feed your equipment. 

Required Tools & Equipment

• PVC glue and primer
• 1/2" Union Ball valve - x1 for each branch of the manifold
• 1" Tee fittings - x1 for each branch of the manifold
• 1/2" PVC pipe
• PVC Pipe Cutters
• 1" x 1/2" slip Reducer fittings - x1 for each branch of the manifold
• Mask, gloves, goggles
• Sharpie

1. Drain the return line

Turn off your return pump and rain the return line. Be sure water will not back-siphon from the display while you're working.

2. Cut the PVC return line

Mark the location you're going to install the manifold on your return line using the Sharpie. Use the PVC Pipe Cutters to cut your existing 1" PVC return line.  Cut an additional 1" section from each side of the new cut to create a 2" gap in your PVC return line.  Sand and wipe those new cuts to be free of any burs so they are clean and prepared for cement. 

3. Insert the 1" Tee Fitting

The 1" Tee Fitting can now be inserted and positioned onto your return. Twist the Tee Fitting so the leg or branch is facing the most ideal direction to feed your extra equipment. Use the Sharpie to draw a straight line on the Tee Fitting and PVC pipe to mark the alignment.

4. Cement the 1" Tee Fitting

Remove the Tee Fitting and grab the PVC cement.  Add cement to the inside of the Tee fitting and outside of the PVC pipe and glue it into place.  Use the Sharpie marks to ensure your alignment is correct because the cement cures fast, really fast.  

5. Cement the 1/2" Reducer

Cement the 1" x 1/2" reducer fitting into the open leg of the 1" Tee Fitting. Remember to put glue on the outside of the reducer and inside of the fitting, and give it a 1/4 turn when pushing it into place.  Wipe up any glue drips immediately. 

6. Cut a short length of 1/2" PVC Pipe

You will need a short length of 1/2" PVC pipe to connect the 1/2" Union Ball Valve to the Tee Fitting. Using the PVC pipe cutters, cut a 2-3" piece of PVC which should be plenty long enough. 

7. Attach the 1/2 Union Ball Valve

Cement the short length of 1/2" PVC into the reducer.  Before cementing the 1/2" Union Ball Valve, detach the valve from one-half of the union.  This will eliminate the risk of glue entering your unions and sticking them together. Glue the union onto that short length of PVC sticking out of the reducer.  Once it cures, reattach the union ball valve. 

You can now use PVC or soft plumbing to connect your extra equipment directly to the  1/2" ball valve. Keep the valve closed when the manifold is not in use.