One of the first pieces of equipment most will purchase for their aquariums will be test kits. Test kits are an integral part in any marine aquarium keeper’s tools in trying to properly maintain a thriving aquarium. The responsibility of maintaining proper conditions for the animals we choose to raise begins with two simple principles: patience and stability. When used from the beginning, quality test kits will provide us with vital information for stocking and maintaining a stable aquarium. Given the importance of quality test kits, there are some critical points to consider when choosing test kits. For the sake of this discussion I will focus on marine aquariums but many of the same points will apply when choosing test kits for a freshwater aquarium.

The first thing to consider is which kits you need and why. There are numerous articles and books that outline this topic and your choice will depend on how you decide to stock your aquarium (fish only, reef aquarium, most soft corals/ hard corals, new/well established setup etc). For the marine hobbyist the standard test kits that should be on every hobbyist’s shelf should include alkalinity, pH, Calcium, magnesium, nitrate, nitrite, phosphate, and ammonia.

After deciding which kits you will need to purchase you are now faced with the many different brands, prices and types. For the most part there are two types: colorimetric and titrimetric tests.

  • Colorimetric test kits are quite simply a test that forms a color. Generally you will add a reagent or reagents to the water you are testing and match the color with a color chart that will determine the amount of the substance in the water you are testing for.
  • Titrimetric test kits again use a reagent or reagents of a known strength to the test water until a reaction occurs, usually a color change. Unlike the colorimetric test, the titration test will usually have you count the drops of the reagent or refer to a chart that corresponds to the amount of reagent used, which will give you the concentration of the substance you are testing for.

A common misconception about different brands of test kits is that they all use different methods for testing a given substance. In general most test kits are using the same or very similar methods for testing a given substance. This is an important point if you are color blind or have difficulty seeing small changes in color, as a colorimetric test kit may not be a good choice and you may want to consider an aquarium controller or a monitor if one is available to replace a certain test.

So if all test kits are using similar, if not the same methods, than what makes one brand a better choice than others? The answer is simple. ALL test kit companies must make compromises in order best serve their intended audience. For some price is the main factor in which the compromise will come in the form of lower quality reagents, less expensive testing materials (plastic vials, droppers, syringes, instructions) and inconsistent handling procedures. These test kits are usually very simple to use, however they are also usually inconsistent from kit to kit.

On the other end of the spectrum you have test kits that do not compromise on price but make their compromises on ease of use. With these test kits you may get quality testing components (glass vials, lab droppers, latex free syringes, clear instructions) and quality reagents. However, these kits may also require a few more steps in order to get very high sensitivity that for some is unnecessary and generally be designed with a chemist in mind instead of a hobbyist. With this and our initial goal of keeping stability in our aquarium in mind, you must decide what compromises you are willing to accept when purchasing a test kit. Here are a few key points to consider when evaluating test kits prior to purchase.

  • Accuracy and Consistency
    For most of us, there is really no way of testing how accurate a test kit is without finding a lab that is willing to do this and is setup for marine water. With some of the higher end test kits, they will offer independent validation of their test kits but you will have to check with each manufacturer to see what process they use to ensure accuracy. When looking at a kit be cautious of kits that do not have quality parts as this is usually a good indicator of the quality of the reagents as well. It is a good idea to purchase new kits a little before you use up prior kits so you at least know that the kits are testing consistently. Another good thing to do is to always store test kits in a cool dry area. ALL test kits are heat sensitive and all test kits should have a clearly marked expiration date and keeping test kits stored properly is key to keeping kits in proper working condition.
  • Sensitivity
    This is a bit tricky. As with accuracy, Sensitivity is something that is difficult to quantify without the help of a lab. In some cases a test kit may offer very high sensitivity but may not be very accurate or consistent from batch to batch, so the high sensitivity is not useful. When testing certain parameters (i.e. Phosphate, Nitrate, Ammonia) very high sensitivity is useful and should be a priority, while in other parameters (i.e. Carbonate hardness, Magnesium, Calcium) accuracy is much more important and high sensitivity should be less of a priority.
  • Ease of use
    This is often an overlooked point when initially purchasing a test kit. It is important to have quality test kits but if the tests are difficult or tedious to perform the likelihood of staying consistent with testing decreases. When purchasing a test kit, we must be realistic about how much time we want to spend testing different parameters and find a kit that meets your individual needs. Also seeing differences when the color changes, should be readily apparent. Otherwise if it is difficult to ascertain that the color has changed, despite a kit being accurate it is relatively useless.
  • Safety
    Another important and often overlooked point is safety. Many of us have children around our aquariums and even households without children should be aware of the danger that some of these chemicals pose. Proper labeling, childproof locks and non or less toxic reagents are all a very good sign that the test kit company has not made compromises in this area. While these test kits usually cost more it is something to consider as some of these chemicals can be VERY dangerous if misused.
  • Manufacturing and handling
    This is something that you will likely need to contact the manufacturer and ask about but is a crucial part of how your kits arrive to you. As with anything there are many different ways in which test kits can be manufactured and handled before getting to you. Ideally you are looking for a kit that is manufactured in a laboratory and shipped properly and stored in cool conditions. If you are purchasing online ask your sales person how the test kits are stored.
  • Customer service
    With even the best procedures and quality test kits, problems and damage can occur, so it is wise to purchase from a retailer and a company that properly supports their products. In the case of questions about test kits you will also want to purchase from a retailer that has technical staff that has been trained on these kits or can direct you to the manufacturer that can help answer questions and offer suggestions.

In closing, testing equipment is a very important part of our system. With a little research and keeping in mind the points mentioned in this small article you will be able to find a test kit that suits your needs. In the best case this will be a test kit that is well-made, accurate and easy to use. Price should be a secondary consideration as even with the most expensive kit the cost per test is usually only pennies more than a cheaper less accurate kit.