To date, phosphate test kits have consisted of a bottle or tube with a liquid that has to be added drop by drop to a water sample. The idea is to count the number of droplets that are required to produce a sudden change in the colour of the sample. The number of droplets equals a given phosphate concentration. This is a relatively laborious method that is not very accurate given that the size of a droplet can vary considerably, depending on how hard you squeeze the plastic tube. The Microbe-Life Phosphate Test Strip is much simpler: Fill one of the tubes with water up to the top line. If the sample consists of freshwater, place one test strip into it. If the sample consists of saltwater, place two test strips into it. Move the test strip or strips slowly up and down for 20 seconds. Remove the test strip or strips and throw away. The colour of the water sample in the test tube corresponds with the following phosphate concentrations: Yellow = 0.0 ppm (parts per million), Green = 0.2-1.0 ppm, Blue = >2.0 ppm. Place the test tube in the white space between the colours on the colour card. With the card held underneath the tube, move the tube from one colour to another until you get the closest match (as seen from above). The colour that comes closest to matching the colour of the water sample gives the phosphate concentration. Make sure you perform this colour match within 30 seconds. The test kit comes with a colour card against which you can hold the transparent test tube to see which colour (and hence which phosphate concentration) comes closest to matching the colour of the water sample. The great advantage of this test method is that you don’t have to count droplets, because the reagent is already on the test strip and simply dissolves as you move it up and down in the water sample. All you need to do is compare the colour of the sample with the colour card.