I use airlift pumps in my garden as a "research project" to see if they can become useful enough for more general gardeners. I have used them in a fish pond, in pond filtration, in fountains, in compost tea making and in "pallet gardens" Airlift pumps are very simple to make but A major problem with all airlift pumps is that the physics of how they work is extremely complicated and the "burping flow" looks much the same whether they are running fast or slow. And so there are no figures available for how well or how badly they work under different situations. My plan is to change that. I am going to measure their performance under a range of conditions and graph the results so that people can make the best pumps for their own situations.

## Step 1: Constriction Airlift Pump Diagram.

There are many things to measure. Height you pump, air flow, water flow, submergence tube diameter. And all these things in all their combinations! It is overwhelming!

## Step 2: The Test Rig.

There are so many things to measure in so many combinations! So I decided to make something to test 3 sizes of tubes in one go.

## Step 3: The Air Pump

Little old marina 200 bubble pump for an aquarium did the testing. It is about a year and a half old so it is not working perfectly.

## Step 4: Results!

Here are the results of nearly 2 days in simple graph form. And I will pop it in in video too. There is a lot to explain so don't be afraid to stop and pause as you watch the video.

Rocking the science! Well done!
<p>Thanks a lot for the experimental data! this is very useful for me, I am making plans for a window aquaponics system, and I was really wondering what the influence of tube diameter really is on water flow, as well as the air-pump needed to actually get the water high enough. I am aiming for a system 2 to 3 m high, and I guess I should keep that in mind when I choose my fish tank to get the necessary water pressure.</p><p>thanks again for the data!</p>
I think there is a rough inverse relationship between the diameter squared and the limit to the height you can pump. Just from my preliminary results. (So the limit for 1/4 inch tubing seems to be about 15 times the submergence) and the limit for 3/16 inch tubing is likely to be around 25 times the submergence. (But in either case, you will not be pumping a whole lot of water. ) 3/16 inch tubing will require more frequent cleaning. I use a long wire to clean them or one of those &quot; foot pumps&quot; for pumping up air mattresses. Just blast air through the tubes to blow out the &quot;biofilm&quot; of algae that will from.