請參考 Mardel CopperSafe 銅藥的說明
(One dose lasts for one month. 4 oz doses 100 gallons)
...
CopperSafe, when used as directed, maintains a total copper level of 1.5 ppm to 2.0 ppm in the water. CopperSafe remains active for over one month in the aquarium. Levels of 0.3 ppm free copper are recommended...