I was excited to give the t-valve a try… and it works at 9 ft. That will be enough height for 8 bottles above my tank.
http://www.youtube.com/watch?v=mk1Ob7W7WFo&context=C3cbd6cdADOEgsToPDskLk8Cwd3j5ZvNMU5K-p-Hqq

http://www.youtube.com/watch?feature=endscreen&NR=1&v=7LQQbSDDRBo
In my previous attempt it took both air outlets at full power to keep a flow going for 6 bottles. With the t-valve I have barely any air passing through my 3-way air flow splitter and the air pump is at its lowest level.

So my only concern at this point is the slowness of the water flowing through the check valve. I’m currently using the cheapie blue check valvem but I have ordered a few of the green ones recommended by Meike http://our.windowfarms.org/2011/01/26/low-water-level-pulser-pump/ Hopefully that will help.

^air and water move up the tube.
^
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|_ t-valve_____ tube with air from air pump
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short tube with a check value at the end allows water up into the tube but no air bubble can exit down into the fish tank. The check valve sits just above the bottom of the tank.

Way cheaper than buying the rigid tubing and bicycle inflation needles. Would anyone like to have my needles? I won’t be needing them.

I put together a 6 unit column this weekend. It hangs above my rubbermaid fish tank. I’m trying beans first then I’ll move on to other plants. I tried to make it an 8 unit column but the water didn’t want to travel up the sixth. I picked up the 1.5 liter electrolyte water bottles from Trader Joes. Because I prefer a straight sided container but I had to hot glue in a little half inch lip inside the water bottle to get the net pot to stay in place at the opening and not fall to the bottom of the bottle. I used the two bicycle pump needles in drilled holes a few inches up the tube and added a sponge filter over the bottom of the tube to keep the snails and small fish out of it. The tanks is actually my cat’s ”fish TV set”. So it’s not much to look at but fully cycled and already on the floor. Ph 7, Nitrates 5.

Sorry the video is sideways Ha! I come from a photoshop world where images are rotated. Not an option with video. I’ll reshoot tomorrow.
But you get the idea.
http://www.youtube.com/watch?v=mYTrNfT7DC4&feature=context&context=G2004994AUAAAAAAAAAA
http://www.youtube.com/watch?v=p1XmrceLLGw&feature=g-upl&context=G2004994AUAAAAAAAAAA

Goto http://our.windowfarms.org/groups/aquaponic-window-farms/