Making The 20 mm Siphon

Since I am making two sets of siphon for Abu Dhabi, its best I use this opportunity to document it in detail so that it can be a reference for those that want to make it.

This post will be in parts.
  • Making Bell and Strainer
  • Making the Stand Pipe
  • Making Siphon Outlets
  • The Installation
Making Bell and Strainer

This mini siphon make use of 50mm/2" PVC bell with end cap and 82mm/3" uPVC for the strainer with vent cap for cosmetic purpose.
Above are made for 12" Growbed and firstly the 82mm uPVC need to be cut to about 11", you may cut it longer depends on how you are installing yours. The Vent cap take up that additional inch to make the growbed 12 inches.

Before cutting I normally use an A4 paper wrap around the pipe to ensure square cut, so use an A4 paper mark the necessary lines then cut the pipe to length.
There you go, I make two since they asked for two. I use hacksaw blade to cut, initially make a trace cut around then cut it deeper.
Next the 50 mm bell, similar to the uPVC mark it with A4 paper roll to get a square cut, but this time I square the uncut pipe first.
On the ends its easier to use a snip for cutting it. I use snip for all large pipes outer ends to square it.
I cut this pipe to length after gauging it with the strainer pipe, this to ensure matched height.
So after putting the end cap, insert the 50mm pipe in the strainer and mark it to length as below.
Take it out remove end cap, measure the length required double it which would be in this case here 10 and 1/4 times 2 so about 20.5 inches.
So far you will have these below.
Use hole cutter to divide pipe into to by drilling around, 4 or 5 holes will do. Since this is a 50mm pipe and I use 25mm hole saw to cut.
Cut in between the 2 large holes above as marked and you would end up with two piece of 50mm bell pipe.
Next to make holes on the 82mm uPVC strainer to complete this part of the siphon making. I use 8mm Tile drill bit, this is best for plastic. 8mm or bigger normal drill will do, but after making so many this is the best. A Tile Drill Bit
These strainer holes I do "free hand" rough estimate on spacing "fuzzy logic", nothing to worry about. The first row is the hardest to do, next will just a repeat and reference to the first.
I normally do about 4 rows, this one I make 6 rows. Strainer holes most important at about last 1/3 of the growbed water height, because everything need to go downward. No point of having strainer holes on top of pipe. This arrangement also will make sure plants roots will not have effect on strainer, well at least slower effect.

BTW in Aquaponics, using Siphon with strainer plants root don't really have significant affect on it. Since in Aquaponics nutrient is concentrated every where, plant root will tend to be localised and don't need to travel far.

Ensure good drainage with a good siphon will result in better aeration so the roots will not go far.

Finally you will have these done.

Making Stand Pipe

Stand pipe is simple to make, this is using reducer but for comparison the flare trumpet type will also be shown.

What you need for the stand pipe.
  • 20 mm bulkhead fitting (tank fitting)
  • Short piece of 20mm PVC pipe
  • 32/20  mm reducer (25/20mm would work too, I prefer this size)
  • 32 or 25 mm PVC pipe for extension to adjust water level.
If you have difficulties in getting that reducer, just flare the 20mm PVC to make the funnel, more on that post : Here
I drill a 5mm hole on the Bulkhead fitting as a drip hole, this is optional but I recommend it if you need to switches off the pump at night. Otherwise its an optional item. Best to have.
Fully assembled this what you get, the flare stand pipe is on the right for comparison.
On the flares stand pipe, you need to make different flared length if you want to adjust water level. On the stand pipe that use reducer you only need to change the extender to do that.
Again I made two for the set heading for Abu Dhabi, Flared Stand pipe just for comparison actual shape must refer to its own post.

Making Siphon Outlet

Outlet play some part in getting good reliable siphon, don't view it as an after though it just as important as the rest of the siphon. Apart from making siphon more reliable, these outlet can be made to aerate fish tank better. There is also a special High Water Outlet I made for my growbed situation and can be referred on its link : Here

Parts Required are
  • 12" of 20mm/3/4" PVC - 1 off
  • 3" of 20 mm PVC - 2 off
  • 20 mm elbow - 2 off
  • 20 mm threaded adapter - 1 off
Before assembling it, drill holes on the 12" down pipe. half its length will do. Do not overdo it, too much that will weaken the pipe.
I use same Tile drill bit to do these holes.
Assembled two for the road, sexy pair of legs. These should work beautifully and slight changes in its measurement don't make any different in its performance.

The Installation

Installing the siphon is easy once all parts done. Below are all parts for the siphon.
and the grow bed is drilled with a 25mm hole saw to take the stand pipe.
How to Make My 20mm Siphon Installation Video:


  1. What size grow bed will this siphon support?

  2. @Judoman, it should support up to 4'x8', it could support bigger provided good drainage done on growbed bottom.

    Actually the smaller the siphon the better it will drain a growbed, due to smaller water flush will give more time water from further away to be drawn towards the siphon.

  3. PVC tool pipes even in planting pvc contributes well. makes life easy.

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