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Water & Air Quality Monitors water-proof environmental equipment |
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| Dryden Instrumentation | ||
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| RLU relative light monitor of bacteria activity | buy or view price | ||||||||||||||||||||||||||||||||||||||||
The Dryden Aqua RLU relative light unit monitor measure the ATP (adenosine triphosphate) concentration of the water. A sample of water or a swab of a surface is taken with the stick. Enzymes on the tip of the stick then react with ATP in the sample and give small flashes of light. The monitor measures the number of light flashes and this is a measure of ATP concentrations. All bacteria, and living organisms secrete ATP or release ATP when the cell ruptures or dies. ATP analysis is therefore an indirect means of measuring the biomass of bacteria in the system. It is not a measure of living bacteria concentrations but rather a measure of the biomass of bacteria at some location in the system. The reading takes just 2 minutes, and in our opinion the results are more important and useful than standard bacteriological analysis. For example, if you measure the viable bacteria levels in a swimming pool, the microbiological results may give a reading of zero, if there is free chlorine present at 0.5mg/l most planktonic individual bacteria are oxidised in under 30 seconds. So the reading in most pools will usually be zero, but this does not mean to say the water is safe. Indeed there may be a huge biomass of pathogenic bacteria such as vibrio or legionella in the pipework, balance tank or sand filters. Regular bacteria analysis usually gives a zero reading, but when you conduct an ATP check there may be a high reading. A high reading means that there is a large biomass of living bacteria in the recycled water treatment circuit. For example, bacteria will be living in the pipes, balance tank and filters, or in the grout between the tiles in the pool. Dryden Aqua have taken many measurement of swimming pools and Spas and have related the RLU readings to water quality and biological safety of the system. There are many manufacturers of RLU units, the table below, only relates to Dryden Aqua equipment.
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