The Phosphorus Ultra Low Range Checker HI736 from Hanna Instruments is a device which you can use to detect phosphorus concentration in your tank. This is important because high levels can cause corrosion. This checker uses the ascorbic acid method and is capable of providing very precise results with +/-5 ppb +/-5% reading accuracy. One reason why these colorimeters are so precise is the fact that they use specialized reagents and each one is designed for a single parameter so contamination cannot skew the results.
These handheld colorimeters have proven to be popular because they combine qualities in ways that were not possible previously. They are affordable and easy to use like traditional chemical kits but they are also capable of providing extremely accurate readings like expensive professional instrumentation.
Using this checker is very easy. First you need to zero the colorimeter with the water sample. Then you add the reagent and place the vial into the checker. All you have to do is press a button and it will give you an accurate reading of current phosphorus levels.
At just 64 grams, the instrument has been designed to be light and small. This means that it is easily portable so you can get accurate on-the-spot readings. It only has one button and also features a large LCD display so that the readings are clearly visible. It is powered by one AA battery. The standard kit comes packed with 2 sample cuvettes with caps, 6 powder reagents for phosphorus, battery and instructions.