With reference to system components, according to few consultants surveyed, biofilters and solids removal are by far the most important, in order to optimize water quality (i.e. for healthy fish and good system performance). However, as the solids concentration increases within the system, increasing fish susceptibility to stress (higher FCRs are obtained, with slower growth) and increasing carbon dioxide concentrations to risky levels, the CO2 removal becomes a relevant aspect, sometimes not considered, at the designing stage; CO2 devices are missing in nearly half of the systems, as unforeseen situations and risks are ignored by the designers or installers, when calculations are. An inadequate control over water temperature and the absence of pH control are also identified issues for some systems; among the mentioned causes
the inadequate calculations, perhaps based upon laboratory and small scale or trials results are highlighted. One of the most reported issues, particularly affecting on-growing systems (as they produce fish directly for the market), is off-flavors’. Five out of seven ongrowing companies reported that this has been a problem, although the product is depurated, over between two days and six weeks, before sale.
With reference to system components, according to few consultants surveyed, biofilters and solids removal are by far the most important, in order to optimize water quality (i.e. for healthy fish and good system performance). However, as the solids concentration increases within the system, increasing fish susceptibility to stress (higher FCRs are obtained, with slower growth) and increasing carbon dioxide concentrations to risky levels, the CO2 removal becomes a relevant aspect, sometimes not considered, at the designing stage; CO2 devices are missing in nearly half of the systems, as unforeseen situations and risks are ignored by the designers or installers, when calculations are. An inadequate control over water temperature and the absence of pH control are also identified issues for some systems; among the mentioned causesthe inadequate calculations, perhaps based upon laboratory and small scale or trials results are highlighted. One of the most reported issues, particularly affecting on-growing systems (as they produce fish directly for the market), is off-flavors’. Five out of seven ongrowing companies reported that this has been a problem, although the product is depurated, over between two days and six weeks, before sale.
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