It wasn’t immediately clear how an air pump is supposed to push water to the top but the method is apparently quite sound. Thanks to the pre-assembled tubing by SchreberMeister connecting the valve to the bottle and the pump was easy. Up until this point I had not read any of the posts on windowfarms.org, so I was basically winging it. That came to a abrupt end when I filled in some water and switched on the pump. It was a delight to see the air going into the bottle and doing something, but certainly not what it was supposed to do.
For the interested reader let me sum up the way it should work: The air valve pumps air into the bottom bottle that contains about 60% water. You then slide the tube that goes to the top over the valve, which I had forgotten to do, so all the air was simply creating bubbles in the bottle. I found it quite difficult to find a detailled explanation quickly.
After correcting the issue and sliding the plastic tube onto the valve and adjusting the pump pressure I had the Eureka moment. Water was flowing to the top. It was at this point in time that I realized why the included timer was set to run for about 5 minutes every two hours: The pump is actually quite loud and even for me being used to multiple computer fans running all the time that would have been interesting to work around.
Just as I turned around to attach the second valve I heard bubbling. Not good, I ensured that tube was still over the valve, it was. But still air was flowing out of the tube into the bottle. Some research on windowfarms.org led to some tips:
- Tube should be at an angle. This is theoretically the case with the SchreberMeister kit. Even though the plastic tube supplied is cut straight at the ends it sticks out of the bottle, so it can’t be completely straight in the bottle and therefore should be at an angle at the bottom.
- The tube shouldn’t be touching the floor of the bottle (in this case the cap) in order to allow water to enter the tube.**
- More water pressure may be needed to lift the water in the column.
I tried all of these but the system just wouldn’t perform for longer than a couple of minutes. I emptied the system* and replaced the first with the second valve. After some adjusting that valve performed just as expected without any hick-ups. I’m going to observe this for now (while my seeds are growing) and see if I can come up with a solution and maybe have a talk with the SchreberMeister team.
So bottles are set-up and water is circulating (at least in one of the columns). Next up the plants.
*Always, really always, use a bucket – don’t think you can empty the bottle into the container you used to fill it with, it will result in a flooding.
**A quick fix was actually to lift the tube about 1cm quickly and then push it back down. This caused the system to work for a couple of minutes