Build a long reach pvc water pump, handy for pumping right down to the bottom, and easily transfer water between rain barrels without resorting to the small plastic 5 litre paint buckets that fit the opening.
I had hoped that this small scale pumping windmill copy would start siphoning once I pulled the plunger past the T piece, alas the reducing internal diameter of the T is smaller than the internal diameter of the 50mm pvc pipe which makes it difficult to pull the plunger past the T.
Experiments have shown that the standing water level needs to be halfway up the inlet pipe, roughly 500mm high for the syphoning action to occur.
A check valve, made out of a hollow plastic ball found in roll-on deodorants, right at the bottom of the inlet pipe, ensures that you dont have to pull on the plunger like a stark raving lunatic in order to raise water.
~Now updated with a better valve~