Gravity Header Manifold prototype #3 tutorial

This article covers the creation of the 3rd prototype “Gravity Header Manifold” – designed to route water at low pressures – for Aquaponics or Hydroponics. The many outflow pipes led to spray bars for aeration, grow beds, glass fish tanks, and bio filters. This was the most recent design built, and it is running fine after more than two years, with zero maintenance and zero blockages.

Unlike the previous versions of the header, this design automatically starts all outflows instead of relying on permanent siphons – so if there is a short power outage or interruption, the system will restart itself. This Tutorial can be used to build a V3 or V4 Gravity Flow Header Manifold Show Below.

This is a pretty complex project if you’re a beginner crafts-person. The manual start, permanent siphon version was a LOT easier to build, with less plumbing and pipe management. Click here for prototype V2 Tutorial.

For more information about the Gravity Header Manifold projects, how they were used, and how they were connected, see: ////ARTICLE COMING SOON

Preparing the jug and frame.

Pick out a jug or other container, and build a timber box to fit. The jug sits on a small shelf, just make sure the gap under the shelf is big enough that you can reach in there. — Pick out a jug or other container, and build a timber box around it as shown. The jug sits up off the bottom on a small shelf – make sure the gap under the shelf is big enough that you can reach in there comfortably. Pictured is a 5L jug with the top cut off. Make sure to leave a gap between the top of the jug and the top of the box.

Cut a piece to sit on top of the container as shown. The sloped edge can be any angle, but steeper is better. You want it to cover at least half of the height of the container. — Cut a piece of timber to sit in front of the jug as shown. The sloped edge can be any angle, but steeper is better. You want the slope to cover at least half of the height of the jug. I roughly chamfered the top and bottom edges freehand with a jigsaw, but it’s not totally necessary.

The box laid out. Don't worry about the holes in the bottom yet, we're getting to that. — The box laid out. Don’t worry about the holes in the bottom pieces yet, we’ll get to that.

Roughly lay out your container and box as shown, then mark and drill holes for your output pipes. I used 6mm inner/ 8mm outer diameter vinyl tubes. — Roughly position your container and box as shown, then mark and drill holes for your output pipes. I used 6mm inner/ 8mm outer diameter vinyl tubes for most of them.

Using a spade bit or small hole saw, drill through both the shelf and the bottom of the box as shown. Make sure the holes are reasonably well lined up so the pipes sit straight. The easiest way to do this is before the box is screwed together.

Notes on the stand pipe drains

Make sure the top of the pipes will be at least 50mm/2in’ lower than the top of your jug/container.
Make one slightly taller than the other – the lower one will be the primary drain, the higher one will be the secondary drain in case the primary one gets blocked. (I had the primary drain leading to a sealed bio-filter. Click Here for the Biofilter Prototype #2 Tutorial.)
Make sure that they are the right diameter so they can snugly fit inside or outside the pipes/hoses you plan to connect to them. The ones pictured almost perfectly fit some spare garden hose I had lying around. I just pushed it up into the drain pipes – and they worked fine for years with no seal or plumbing, since the outflows creates suction anyway. Any small leak will become a Venturi – air will be drawn in instead of water pushed out due to the low pressure gravity design.
Don’t put them too close to the edges of the box, it will make it harder to plumb them through your jug/container.

Screw the box together, and begin the pipe assembly.

Once you have your stand-pipe holes drilled, screw the box together, but leave off the top piece. Drill pilot holes before putting in your screws – to be sure the timber won’t split.

Line up your container/jug and drain pipes as shown. Trace around the pipe as best you can, enough o you can see where the center is when drilling the holes. Tip: Mark it out down near the bottom of the box as shown. If you mark the pipes up near the top of the box, any slight error in the angle of the pipes is multiplied. — Line up your container/jug and drain pipes as shown. With a pencil, trace around the pipes as best you can, enough so you can see where the center will be when drilling the holes in the jug. Tip: Mark it out down near the bottom of the box as shown. If you mark out the pipe positions up near the top of the box, any slight error in the angle of the pipes is multiplied.

Fixing the drain pipes into position using twists of wire. — Fix the drain pipes into position using twists of wire. Twist it with pliers until tight, it will be very strong. Cut off the excess twisted wire, or bend it around the back – cut wire can be quite sharp – safety first!

Start attaching the pipes, leaving them long enough to reach a few centimeters (1 inch) into the jug. I used cheap plastic fixings, but you could tie them on with with wire threaded through holes in the timber instead. — Start attaching the pipes, leaving them long enough to reach a few centimeters (1 inch) into the jug so there is enough surface area to seal them with silicone later. I used cheap plastic fixings to hold the pipes in place, but you could tie them on with wire threaded through holes in the timber instead.

Notes on the holes in the base

Apart from the holes for the two PVC stand pipes, you can drill the holes wherever you want. I put mine close to the back of the box so they would hang closer to the wall when the header is installed later. Just make sure that you can tell the order of the pipes as they enter the jug, mine were highest priority on the rightmost hole, lowest priority to the left. You can drill these at any time in the construction process – except for the stand pipe holes.

Time to seal the stand pipe holes. Slide your jug up a little as shown. Spread some silicone all around the circumference the PVC pipes down near the 'shelf' piece. Gently slide the jug down onto the silicone. When the jug is in place, spread some silicone on the holes from the inside of the jug as well. — Time to seal the stand pipes to the jug. Slide your jug up a little as shown. Spread some silicone all around the circumference of the PVC pipes down near the ‘shelf’ piece, then gently slide the jug down the pipes onto the silicone. When the jug is in place, spread some silicone on the holes from the inside of the jug as well.

Install some garden hose and tie it to the box with two holes and piece of wire. This is where water will enter the header. I used two for small pumps, with one spare. — Install some garden hose and tie it to the box with two holes and a piece of wire. This is where water will enter the header. I used two for small pumps, with one hose as a spare for later expansion. The spare can also act as an ‘out’ pipe, but you have to start the siphon manually.

Finish off the box, and add a door. This is important, you don't want light reaching the water or slime will grow. — Finish off the box, and add a door. This is important, you don’t want light reaching the water or slime will grow inside. Trim your pipes to length to make them look neater.

Done!!

Add latch or hasp to keep the door shut, and paint the exterior with some raw linseed oil or any other non-toxic sealer. I installed mine approx 1.7m / 5.5ft above my main Aquaponics tank and connected two pumps. The pressure from the 6mm output pipes was sufficient to run aeration spray bars and prototype grow-beds, as well as run a bio-filter from the primary drain pipe.

See the full article on the Gravity Header Manifold for information on how pipes are connected and capped. /// Coming soon