Protocol
We tested Potable Aqua on water collected from a puddle. This water was very clear, with just a few leaves floating on top. We followed the manufacturer's instructions precisely. We spread 140 micro-liters of water on each plate (we used LB media) and grew the plates over night at 37 degrees Celsius (approximately body temperature).
The Plates
We collected puddle water and plated 140 micro liters of it before treating it to use as a control. We then measured out 32oz into a nalgene bottle, added the Potable Aqua Tablets, waited 15 minutes and plated 140 micro liters. We then waited another 15 minutes (30 minutes total) and plated another 140 microliters on a new plate. During treatment, we noticed that that Potable Aqua does cause the water to have an odor. We did not taste this water, as we did not yet trust Potable Aqua.
Here is the picture of the plates. On the far left is the untreated water. In the middle is the Potable Aqua that was allowed to act for 15 min. On the right is the Potable Aqua that was allowed to act for 30 min.
Our Conclusions:
Though it may be hard to see in the pictures, there is only one colony on each of the treated plates. When doing experiments like this, each colony comes from one single bacteria, so clearly, Potable Aqua killed the majority of the bacteria in the water. Keep in mind that we are not testing for specific microorganisms, just a general mix of bacteria. Potable Aqua does not kill cryptosporidium and is marketed as "bacteriocidal" meaning that it kills bacteria.
