Building a Better Reservoir

I noticed one of my windowfarm columns was going through a lot more water than the others, and realized that it had a slow leak. I’ve been using Deer Park 1.5 liter water bottles, upside down with a hose mounted in the cap, but the plastic is so thin that every time I touch them they get more deformed and “crunched” looking. So today I set out to build a better reservoir.

I used 1 liter soda bottles, which are considerably thicker plastic than the Deer Park bottles and will hopefully stand up a little longer. They’re also shorter, so they fit into the orchid pot (essential for keeping leaks off my floor) much better. I’ve had a few questions about how everything is set up, so here’s a more detailed build.


Drill a hole in the bottle cap slightly smaller than the outer diameter of your water-line tubing”


Push the end of the tubing through and secure with a barb (I cut mine from a t-joint connector I wasn’t using).


Drill two holes in the bottom of the bottle: one the same size as the cap hole, to serve as the water return, and a smaller one to allow air in/out of the bottle. Without the smaller hole, water won’t be able to flow into the bottle due to the air pressure build-up.

To make it easier to connect / disconnect the water return lines, I made a coupling using a short piece of flexible tubing (pushed through the hole in the bottle) and some smaller diameter rigid tubing (from the aquarium store). To connect the water return line, I just slide it over the piece of rigid tubing.


I’ve tried to get a good photograph of the set-up in action that explains the placement of the reservoirs and t-joints, but I think a diagram would be better. I’ve got 3 1L soda bottle reservoirs, one aquarium pump (Tetra Whisper 40), a 4-way gang valve, and each reservoir is connected to a T-joint via 5′ of 1/4″ diameter flexible tubing. The lift tube for each column is 5 feet of black landscaping tubing, which claims to be 1/4″ but is considerably thicker than the water supply tubing. The water return line is the same clear 1/4″ tubing I used for the water supply. The whole setup is contained in a tall orchid pot I got from Target. A Rubbermaid bin would work just as well, but the orchid pot looks better.

Black vs clear tubing is a personal preference thing. The clear is considerably easier to debug, but you need to be fairly vigilant about cleaning it or you’ll get algae build-up.

For the sake of my crude illustration skills, I’ve only drawn one reservoir and left out the gang valve.

So far nothing is leaking, but we’ll see how things look in the morning. If nothing else, the water tubes have gotten a thorough cleaning over the last two days.


6 thoughts on “Building a Better Reservoir”

    1. When the water line is too short, it’s too easy for air to flow back into the reservoir bottle rather than up into the lift tube, and you just get an air bubble generator. You have to convince the air that going up the lift tube is easier than going down the water supply line into the 1 liter bottle.

      Raising the height of the reservoir bottle accomplishes the same task, since gravity helps, but I didn’t really want to have any more ugly soda bottles hanging in the window.

      Another option would be to have a check valve on the water supply lines, but those are considerably more expensive than the 5′ length of hose.

  1. Thank you for this diagram! I found you by way of one of your windowfarms comments. It helped me solve the escaping air bubbles problem. I’ve got the first column up and am trying to figure out how to add in a second column if I split the air flow tube.

  2. Great idea, thanks. I am using a larger water tank so I think I will try your idea. Where did you find the T-joint? T think that you live near Toledo, the same as me.

  3. Followed the link over from your posts on the Window Farm site and I wanted to say thanks for the pointer to the aquarium gang valve. I now have 5 columns going off 1 small air pump.

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