The construction method of the purification pool is to dig a pit, then discharge it from the entrance and exit and cover it. First dig a pool with a width of 3.5 meters and a depth of 2 meters, build by laying bricks or stones around it, and smooth it with cement. Then, put a sewage storage tank with a width of 2.5 meters and a sewage treatment tank with a width of 1 meter, but divide the tank with a width of 1 meter into two tanks with a width of half a meter.

Secondly, it is necessary to fill some gravel and sand in the pool, but it is best to spread sand with a thickness of 0.3 meters, because too thick sand will block the water and cannot filter it.

After that, the clean water outlet must be lower than the cover of the sewage pool, otherwise the sewage will come out from the cover; The outlet of clean water should be at least 5 cm higher than the coarse sand, otherwise the coarse sand will go with the water and will not work.

Finally, the cover of the sewage pool should be covered with a movable cover, so that even if it is too long to treat sewage, it can be replaced by lifting the movable cover. Moreover, if the sewage pool is too polluted, it can be cleaned by lifting the movable cover.

When making overflow filtration, it is necessary to dig a filter pool with the size of 1/3 next to the fish pond together with the fish pond. The filter pool is divided into small pools, the first layer is physical filtration, and the filter materials filled in it are filter cotton and brushes.

The second filter pool is a biochemical filter pool, which inhibits the growth of harmful bacteria in fish ponds through the adsorption of biochemical balls, activated carbon and other substances. Then there is the sterilization pool, which mainly uses the auxiliary ultraviolet sterilization lamp to kill some harmful bacteria and some parasites in the fish pond.