A brief tutorial on how to construct a basic recirculating hydroponics watering system.

What you will need:

• 3 x 100 litre bags of course grade perlite
• 1 x 50-60litre poly tub (for the reservior)
• 16 x 25-30litre black poly pots (found at most hydro shops)
• 20 x 13mm irrigation straight connectors
• 16 x 13mm irrigation T pieces
• 1 x 19-13mm irrigation straight reducer connector
• 1 x 19-13mm irrigation T piece
• 1 x19mm irrigation elbow
• 1 x13mm irrigation tap
• Air rating hose and a small to medium airator
• 20-30meters of black triple kink irrigation polypipe
• 1 bag of 13mm top hat grommets (it doesn't hurt to get few extra.. as they do come in handy later on down the track)
• Submersible fish pond pump (the one I'm using is an 8500l).
• Finally some shade cloth (roughly 2 meters of each of  a course, and fine shade cloth material. As they go into the bottom of the pots you'll need to be able to get 8 circles from each one).

• Hand held drill (pref cordless)
  
• Serrated steak knife
• 16mm hole saw bit
• 3-4mm drill bit
• I've also got a pair of conduit cutters I use for cutting the hose. Most people may not have these, so just a plain cardboard knife like I've got here is fine.
• Kitchen sieve
  

When you drill a hole there is sometimes a tiny burr and should be removed carefully. I use the steak knife pictured above and find it works really well. I did have a de-burring tool but some scum stole it from my tool box.

THE POTS

The top pot needs a series of holes drilled in the bottom of it to allow drainage, and also needs one drilled in the top just above the top ridge for the watering hose to go through.

The bottom pot just needs a hole drilled at the bottom for the return hose back to the reservoir / heart. Don't drill this hole too low as it needs to be 3-5mm above the inside of the pot or the grommet can't seal properly and it will leak.

Here you can see how they go one inside the other, you can also see the the hole for the positioning of the feeding hose.

The shade cloth is cut into round circles placed into the bottom of the pots ready to wash the perlite.

THE PERLITE

Perlite needs to be washed or it gets powdery and if you just put it straight into the pot it will silt and the drainage be restricted. Washing perlite MUST be done.

Open the perlite bag (I undo the stitching so I can reuse the bag later to throw out the perlite) and just pour it into the bath tub. Using a piece of 13mm hose just hose it as it pours in to help keep the dust down. A dusk mask should always be worn when handling perlite. Continue to fill the tub with water and really wash it thoroughly so all the fine dust will settle to the bottom and the perlite will float on top.
Washing the perlite is very important if this is not done properly then you will have trouble with the water draining back the reservoir, as the fine dust is like silt and will clog just about anything. As you can see there's quite a bit of dust and this is just from 1 bag of perlite.

Once the perlite has been washed you can start to fill the pots, one bag does roughly 4 pots however you still need a little more just to top them off. If you've got the 30liter pots you will definitely need the 3rd bag of perlite.

Set the pot up so the perlite can drain as shown below.

Using a kitchen sieve scoop the perlite out and fill the pot making sure the shade cloth is pressed right to the edges of the pot as you don't want perlite getting through. If you've bought the pot sox then you don't have to worry.

Fill all 4 pots. Its usually only the last one that needs draining however they will all continue to drain, so put them somewhere so the water can't ruin anything. Repeat until all 8 pots are done and draining. This is a good time for a cone/bong/bowl/spliff/doobie/blunt I reckon, then back into the room to put the rest of the system together. 

THE HEART (reservoir)

Lets drill some holes for the reservoir / heart, we'll need 9 holes down the bottom and 2 about 1/3 the way down in the middle. Make sure thay are on the flat side of the tub and not on any curves as they may not seal properly. I've got 9 holes using the last one for a drainage hose. This drainage hose is where you fix the tap to for easier draining and flushing.

Here you can see where the feed hoses connect.

Here's the pump assembly using the 19-13mm T peice then a 19mm elbow piece and 19-13mm connector. Fashion it so the pump splits into 2 lines, each line will do 4 pots.

THE BOTTOM POTS

Put the straight connectors in the pots also in all the other holes you've drilled put in the top hat grommets. A little trick is to use a strong blend of dish washing liquid and water as this also helps preserve the grommets, and helps to get them out easier when you're finished... Saliva works well also.

Once all the grommets and fittings are fitted place the pots into the room and be sure to have the fitting facing the heart. Also you need to have the pots sitting above the reservoir / heart or just below the level of the top of the heart as this ensures everything drains back to the reservoir / heart. Brick pallets work well for this and you may need 2.

As you can see I've used some draws from an old cupboard which works pretty well as they don't sit level and you can have the pot leaning slightly towards the outlet.

CONNECTING THE HOSES

Just run the hose from where the heart sits to the pots and cut. Once you've got all 8 pots done and everything right where you want it cut them to fit, making sure they are right where you want them as it's too late once its done.

Now to assemble the feed hoses. Take 3 T pieces and fashion them so you've got 4 outlets from the one. Each of these hoses needs to be the same length so each pot gets roughly the same amount of water.

Well now everything is put together lets bring the top pots in, as you can see in these pictures the the top pots have the feed rings.

These are simple to make just take a T piece and make a loop drill 8 3-4mm holes at equal distances around the ring. This will unsure the plant gets a good distribution of water. Connect the feeding hoses to the the feed rings and it's probably a good idea at this stage, to fill the reservoir / heart with water and give it a test run checking for any leaks before you go plant anything.