The filter materials should be cleansed at least once a week and replenished at least once a month 过滤物料应至少每星期清洁一次,以及至少每月补充一次。
19 the filter materials should be cleansed at least once a week and replenished at least once a month 19过滤物料应至少每星期清洁一次,以及至少每月补充一次。
If spongy filter is used , more regular cleansing and replenishment of the filter materials should be carried out 如使用海绵过滤器,应更频密地清洁和补充过滤物料。
20 if spongy filter is used , more regular cleansing and replenishment of the filter materials should be carried out 20如使用海绵过滤器,应更频密地清洁和补充过滤物料。
In addition , more regular cleansing and replenishment of filter materials should be conducted if the water quality is poor and or fish stock density is high 此外,如缸内的水质变差及或所饲养的活鱼数目较多,亦应更频密地清洁和补充过滤物料。
In addition , more regular cleansing and replenishment of filter materials should be conducted if the water quality is poor andor fish stock density is high 此外,如缸内的水质变差及或所饲养的活鱼数目较多,亦应更频密地清洁和补充过滤物料。
If circumstances permit , use of layered multi - sand filter comprising both coarse sand and fine sand as filter materials fitted with automatic backwash self - cleansing device is desirable 如情况许可,宜使用包括粗沙和幼沙作为过滤物料的层沙过滤器,而过滤器应设有自动反冲的洁净装置。
23 if circumstances permit , use of layered multi - sand filter comprising both coarse sand and fine sand as filter materials fitted with automatic backwash self - cleansing device is desirable 23如情况许可,宜使用包括粗沙和幼沙作为过滤物料的层沙过滤器,而过滤器应设有自动反冲的洁净装置。