To competently assess a system’s design takes some practice; however, basic understanding and analysis can be accomplished by examining the component parts and their functions. Site visits are essential to understanding how a system has been constructed. In addition to assessing the design and functionality of a system, a site visit allows the opportunity to assess maintenance and cleanliness, both critical aspects of animal husbandry. The importance of a dissolved oxygen meter cannot be overstated when assessing an aquatic system. Oxygen concentration should be measured in the area housing the animals, and it should also be used to help identify areas prone to anoxia because of equipment problems, poor maintenance, or design flaws.
Water quality testing equipment is a requirement for aquatic practice ( See table: A Summary of Water Quality Tests and Recommended Use A Summary of Water Quality Tests and Recommended Use ). Good quality testing kits are commercially available at reasonable prices. Tests can be run quickly, providing data in a timely manner.
The basic parameters to be tested are:
Testing for freshwater and marine systems is similar; however, the total ammonia nitrogen (TAN) test often sold for freshwater use requires the use of Nessler’s reagent, which has two distinct disadvantages: it contains mercury and therefore must be treated as hazardous waste, and it does not work in marine systems. Alternatively, an ammonia test using an ammonium salicylate reagent is recommended. Chlorine test kits (free and total chlorine) are not included in many kits marketed to the aquaculture industry and need to be ordered separately.
Also, a copper test kit and a refractometer (to measure salinity) should be on hand for use in marine systems. If a practice has enough cases to warrant the investment, an electronic oxygen meter is strongly recommended. If working in a rural area where well water is commonly used, test kits for iron and hydrogen sulfide should be considered. For true specialty practices, investment in a saturometer for detection of supersaturation is also suggested.