I can visualise it. Man that's way to complicated than it has to be. Can you get net pots ? Say about 5 inches. 1/4 inch tubeing ?A small pond pump from a garden store or air pump from fish store , a couple air stones. Get dual air pump.. Each 5 gallon bucket can be fitted like this, you can grow trees in them.
1- drill 2 holes near top of bucket for 1/4 inch tubing, black tubing is better. Run tubes through holes and hook up air stones and place on bottom of bucket.
2- cut hole in the top of bucket for net pot, if you don't have net pot use a plastic flower pot and cut slots and holes. Like a net pot.
3- With the lid on and the net pot in place fill with water just to the botom of net pot. Take the top off and mark that on the inside of bucket. Empty bucket and mark 1 and 2 inches bellow the line. This is where you want you nutrient level to stay.
4- Put it all together fill net pot with hydrotron or lava rock for a grill. Beat the lava rock up some with a hammer, to big marble size. Oh and put a well started plant in with it.

That's a bubbler and the grow trees in them, change nutrients every 7 to 14 days.
If you want drip. Go for a small pond pump or the pump you looked at but it sounded kind of high. Aqua via has good pumps and prices. drill another hole run the 1/4 inch tub through it and hook up to pump turn pump on low. Place pump in bottom of bucket. Run the other end that is outside and to the net pot. Run it to one side of the net pot, so you don't get the stalk wet all the time. A piece of wire wrapped arond tube and held to side of net pot.

Keep water level at all times and PH too. What's an aussy exchange rate to the US dollar? Sytems can be real easy.