Article written by: Amy Stone

No matter how well a system is designed or installed, there will always be times when water quality will have challenges. It is critical to be able to test the water to understand the actual challenge.

In our last column, we discussed oxygen meters and the available styles. Keeping with the theme, we will be covering water testing equipment in this issue. In general, water quality for this column is referring to pH, ammonia, nitrites, nitrates, calcium hardness, and alkalinity. However, testing is available for other parameters for all of the methods discussed.

No matter how well a system is designed or installed, there will always be times when water quality will have challenges. It is critical to be able to test the water to understand the actual challenge. Of course, there are times when changes in water quality are expected, and there are times when it is the hidden culprit.

The most volatile parameters can be tested using handheld meters which are an absolute necessity in aquaculture. However, even though there have been small breakthroughs on handheld testing of ammonia, nitrite, and nitrate, there has not been a long-term solution made available to our market. We often get questions about these probes available, and the available scale is not conducive to use in aquaculture. Ammonium probes are manufactured for use in wastewater applications where the demand is higher.

As much as we, as an industry, have begged major manufacturers to build probes effective for aquaculture, the demand is not high enough to pay for the development of the product. One day we hope that the market will
be large enough to get that attention. In the meantime, we do have a few options for testing.

Depending on the size of your facility, testing equipment can be as simple as a wet chemistry test such as those made by LaMotte or as technical as a YSI photometer or Hach spectrophotometer. The accuracy of the tests in all cases is directly related to the end-user and their attention to detail. It is also important to select the proper test reagents for all these options based on both the scale of the results and the type of water it can test (saltwater or freshwater).

Manual Testing
For those tests that use liquid drops or test strips, the end-user is tasked with comparing a known color scale with the test sample. Depending on who is reading the samples, the outcome can vary. While the results can be imperfect, it does provide a general idea of if there is an issue with water quality. This style of testing is the most economical and is generally used in non-critical applications or in situations where it is difficult to support an indoor water quality lab.

Photometers and spectrophotometers
This testing equipment measures the wavelength of the light passing through the water sample with the appropriate reagents. These test systems are supplied with computer programming to be able to scale the sample within the range reflected on the unit's technical specifications. For example, if testing ammonia test code, prepare the sample, and run it through the test.

Each manufacturer has their own protocol for the test procedures, so it is important to read the instruction manuals to ensure the results are accurate. If the sample is out of range, the readout will indicate that, and the
sample will need to be diluted or it is so low that there is no issue at all.

The most popular versions of this style of testing are Hach and YSI. Both systems use pre-measured test reagents. Either a pill or a pillow pack is the typical packaging. This helps reduce user error because they do not need to be measured or weighed out.

Many of these machines have internal memory and can connect to computer systems to help with record keeping. And in some cases, the reagents are interchangeable between manufacturers, allowing the end-user to source the test reagents from multiple sources.

Spintouch
There is one newer photometer system on the market that is made by LaMotte Company. It is their new Waterlink Spin Touch machine. This system uses discs with several test parameters pre-measured. The end-user fills the disc with sample water and then runs it through the photometer. The test discs are pre-determined for which parameters they will test and are available in several configurations, including salt water, fresh water, pool water, and others. It is important to choose the correct discs when ordering to make sure the results are accurate to the application.

At the end of the day, regardless of what style of testing equipment is chosen, it is definitely necessary to have this available on the farm.