Innovating Science Qualitative Coliform Test Kit (25 Tubes)

My daughter used this product for her middle-school science project, to detect coliform bacteria in the Hillsborough River in Florida. The product worked quite well. When 1 mL of river water was added to the test tubes, the liquid in the tubes turned from red/pink to yellow in about 48 hours (incubated at room temperature, nothing special required for incubation). The results were unambiguous: the yellow color is very easily distinguished from the red so there is no question as to what constitutes a positive or negative result. River water that my daughter treated with chlorine or with hydrogen peroxide did not cause a color change, indicating that the chlorine and the peroxide effectively killed the coliform bacteria in the river water. Results were reproducible -- replicates all behaved the same. Here are a few minor drawbacks. (1) We bought two boxes of these, with 25 tubes in each box; 1 of the 50 tubes did not have the proper volume of broth in it, so we could not use it. But 49 out of 50 tubes were fine. (2) When we treated river water with copper sulfate, and then added it to the tube, the broth *immediately* turned from red to yellow, without any incubation needed. This indicates some sort of interference or "false positive" caused by the copper sulfate. It might be that the copper sulfate caused bacterial cells to lyse, releasing the enzymes that interact with the broth? -- that is just a guess, I do not know enough microbiology to know if I am correct, could be way off. But anyway, don't use this product if you are treating your water with copper sulfate. (3) The test is qualitative only, not quantitative. It will not tell you how many coliforms are in the water. I guess if we knew how to dilute the river water and run multiple tests, we could probably get a "most probable number" of coliforms in the water, but that is way beyond a middle-school science project. I would say that this product is very effective and an excellent value for what it is intended to do. You have to be willing to wait 24-48 hours for incubation, and you won't get a quantitative result, but still it worked just fine for my daughter's school project.

My first order worked perfectly. My second order arrived with different amounts of liquid in each vial, and a variety of colors ranging from yellow to orange to pink to red. I could not use the second order at all. Good product when it works, but don't count on a good batch.

I use these to test my rainwater purification system. The various 1 or 2 test kits available become prohibitively expensive -- ~$10/sample on the average -- so I thought I'd give these a try. Simply put, they work for my purpose. Samples from each of four tanks soon after a rain fill showed bacteria (as expected), and water out of the kitchen faucet post-purification remained red (no bacteria, as expected). Just what I want to know. I took off one star because out of 50 tubes, 3 or 4 were grossly underfilled and one had already changed color to yellow when I received it. Still a good value for my purposes.

This is going to be a long winded review, but it is educational and informative, and can SAVE YOU MONEY. I was looking for a water well test kit for coliform bacteria only. This is because a test for coliform bacteria is an excellent way to find out if your water well may be contaminated with surface water or something outside of the aquifer your well draws from, the most common source of residential water well contamination. I found plenty of water well test kits that included the bacteria test but none that were for bacteria only. And the kits aren't cheap if you need to make multiple tests. When a water well has been producing water for years on a regular basis, such as the only water source for a house, and it has had regular tests for contaminants such as metals and fertilizers always come up negative, it's a pretty safe bet that a coliform bacteria test is all that is needed to show if the well has been contaminated. If a coliform bacteria test comes up positive, and there is no obvious reason why, then you should look at your testing procedure and look for a reason why the well may have become contaminated, such as a broken pipe. If you are testing properly then you need to look for the problem. In my case it was a broken pipe. Buy even a spider falling into the well can cause a positive test, even though it won't make you sick. In any case the well must be chlorinated to kill any pathenogenic bacteria. Either you found the problem or you didn't. In any case the water must be tested after treatment. So that's at least two tests. For the approximate price of two tests. And this kit has 25 tests. I had a buried broken pipe in my water system. After repair and flushing I tested for coliform bacteria and it was positive. When I did the test I wanted to make sure so I put the suspect water in one test tube, water sterilized by boiling in another, and water from the toilet bowl that had some fecal matter present (ick). Both the well water and the toilet water came up positive. The sterilized sample test was negative. The test after chlorination also came up negative. So I did four tests and still have 21 tests left. I think this product is a great deal. I think most of the water well test kits are way over priced. EDIT: I tried the kit yesterday because my well water became contaminated. Even though at least a couple years old the stuff still works, changing color in the presence of coliform bacteria.

A few of the media were already turning color and two tubes were empty. The ones I used and my “control” worked as expected.

Follow the directions (not complicated) and the test works great.. I found a warm spot to incubate and my results showed one area of my drinking water system had a problem. Hint: use two tubes for each sample, for Another idea is to use one tube - without any sample added as a control.