How do you keep koi pond water stable?

Koi are hearty eaters, producing a lot of waste and changing water quality quickly, so stocking density must stay low, with only two or three koi per 30 to 50 cm of space. Prepare enough filter media such as bio-rings and ceramic rings to remove harmful substances and host beneficial bacteria. Also use an air pump, since beneficial bacteria consume a lot of oxygen and shortages cause water changes and fish death.

Finally, add EM bacteria two or three times a month and clean the filter media regularly. When cleaning the pond or tank, avoid rough movements that shock the overall water quality.