I have a problem with water height
 

I have built your 11 plant system, expanding it to 16 plant holders as per your instructions. Although we did have some initial leaks, these were repaired and the system has been running several months now with mixed results that probably have more to do with me than the system itself. The plants have really taken off but were slow to start. My problem is this. One of the plastic soda containers overflows. The overflow to the holding tank works. None of the other holders are overflowing. The overflow goes over the end of the bottle. Water seems to get into the bottle from the holding tank ok it just doesn't \ stop at the overflow level like all the others. I have to catch the water in a container and put it back into the holding tank when the pump shuts down. The water drains out of the bottle when the pump shuts down. Is the drain plugged up with something? It drains but real slow? I have made sure the plastic pipes are supported. The plant holders on either side on the same line do\ not spill over. We have thought of expanding the height of the plastic container to see if that might stop the overflow. Any ideas on why this container is overflowing? My e-mail is pstrawser@netscape.net. I love this system. Paul strawser.

Is the intake from your pump right next to that bottle. Sometimes the pump is so strong that it makes the bottle close to the intake rise higher because of the water pressure. Slowing the flow will solve that. It will just take longer to fill your garden.
I also have to ask you. You did remember to drill a hole at the top of the over flow pipe. If you don't the water level will do weird things.