Читать книгу Fundamentals of Aquatic Veterinary Medicine - Группа авторов - Страница 22

Multiple designs from simple box filters to multistage proprietary units can be found in use for home aquaria. For freshwater systems, these typically include a mechanical filter to remove particulate and a biofilter placed afterwards in the return water flow. Often an ultraviolet (UV) light unit is installed to control planktonic algae. In saltwater systems, a protein skimmer is also used to remove dissolved organic matter. Adequate gas exchange is generally assured by the simple water turnover provided by the filter system, although additional aeration is often provided with the use of air pumps and air stones. Ponds will usually have the same components as freshwater aquaria, scaled up to meet the needs of larger fish. The most modern designs will typically feature a prefilter, mechanical filter, biofilter and UV light. Water is returned to the pond via a spillway or waterfall, which assures adequate gas exchange. Designs for these components vary, with some rudimentary systems having only a biofilter and waterfall. As this system relies on in‐pond sedimentation, regular depopulation and cleanout is needed. Public aquaria differ only by size and scale from home aquarium systems. However, some large‐scale water purification equipment is described below. Some examples of aquaculture open and closed husbandry systems (raceways, recirculating, ponds, net pens) are given in Chapter 3. Different systems for different life stages are described in Chapter 10.