No lines on first attempt. I believe it was due to not timing the 5 minute wait time before inserting the test strip. The second test was timed and produced a NOTICEABLE line after 10 minutes.

My recommendation: Use a timer and follow directions closely. It is finicky! Note: Oddly enough, the loaded vial will slightly change the color of the water during the 5 minute wait time (before the strip is inserted) and after swirling it.

We own a pool company servicing vacation rental properties and there was a renter checking in that was having chemo therapy and could not swim in a pool with bacteria. We ordered these test strips so we could test the pool daily according to her doctor's instructions and these worked amazingly well. They were easy to use and saved the day! If you need it, there is also a how to video on You Tube you could watch! Will definitely order again should be need arise.

Good at home kit

We (our pool committee) use this product as a back up to the pool management companies maintenance / chemical control. We do a test once a week. We found 1 week last summer that there was a bad imbalance in the chemicals because of this test....thus we closed the pool for a day to shock and treat the water. We started using this test because we had a large number of children in the neighborhood with swimmers ear and we were suspicious that the pool was not being maintained correctly. The technique for using this product is very specific. You MUST wash your hands and follow the directions carefully! Use a phone to time each step, etc. If you do, you will get accurate results. Whenever I get a positive (positive for bacteria) or blank result (erroneous) result I do a second test to be extra sure. Two positives is an automatic pool closing.

Worked as advertised and give a sense of comfort knowing your water test success or failure