We have discussed the water analysis and how often to test our aquarium water, Now we look at choosing your water analysis kit.
For most purposes a highly accurate test kit is not necessary. For example ammonia, one needs to know only if it is present at all, not the precise amount, since any amount of this toxic compound is cause for concern. But on the other endof the scale is copper, a small difference of 0.1 ppm can be significant indeed, the difference between treating disease and killing the marine fish. It is important to understand that what is meant by accuracy depends upon which parameter one is trying to measure.
Accuracy, the degree to which a test result reflects the real state of the sample being tested, becomes ever so more expensive as the decimal places increases. An instrument of test is accurate to +-10 units may cost only a fraction of the cost of a similar instrument that is accurate to +-0.1 units, representing a 100-fold increase in accuracy. Choose a level of accuracy appropriate to the parameter. A calcium test, for example, can vary by +-20 ppm without causing problems.
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Precision refers to the smallest amount of difference a test or instrument will permit the observer to distinguish reliably. The smaller the increment, the greater the precision and the higher the cost. For example, to measure the difference between 0.01 and 0.02 mg/L of phosphate is more difficult that determining the difference between 12 and 24 mg/L. however, since tiny amounts of phosphate can exert dramatic effects, one needs the more precise test.
Which brand should be used? Easy-to-use test kits are sold at any aquarium shop. As with any product, though, not all brands are created equal. Some kits provide results that are almost suitable for serious laboratory work, while others are so inaccurate as to be practically useless.
For any given brand, the test results may not be equally satisfactory across the entire range kits offered. The company that makes a great nitrate test kit may have a lousy pH kit, for example. For this reason, you should avoid master test kit products that offer several kits in a single package. .
Once you settle for a kit for a particular measurement, stick with it. Changing brands will almost certainly mean that the numbers obtained will differ, making it impossible to compare results from the new kit with results previously determined with another kit. Since spotting a changing trend in tank conditions is more important than knowing the precise value at the current moment, the importance of having consistent test results cannot be overemphasized.
For more information on Marine Aquarium Water Chemistry or the Marine Aquarium Beginners Guide click here.
Recommended Water Testing Kits by Saltwater Aquarium Guide
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