DIY Water Change in a System Planted Tank

Planted aquarium tanks are attractive and provide the perfect ecosystem for most species of fish. There are two types of water change or maintenance practices used in a CO2 system planted tank. Water change amounts and frequency depend on the stocking rate, types of fish and the percentage of healthy plants in the aquarium. The water change schedules are listed for a properly set up and maintained planted aquarium with a properly running CO2 reactor. Always follow the husbandry needs of your specific fish and plant species.

Things You'll Need

  • Tank vacuum
  • Tap water conditioner
  • Water testing kit
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Instructions

    • 1

      Turn off the CO2 while cleaning the tank. Fill a clean bucket with water whose temperature and pH parameters are identical to those of the tank water. Add tap water conditioner (dechlorinator). Remove 20 percent to 30 percent of the water (less for sensitive fish species; more for heavy-feeding fish such as goldfish) without disturbing the substrate. Replace the removed water with the conditioned water. Light vacuuming of the substrate can be performed once or twice a month. (Use care around plant roots.)

    • 2

      A healthy planted tank with a plant-stocking ratio of less than 20 percent substrate availability -- i.e., from 10 percent to 20 percent of the substrate is bare of roots and plants -- requires a topping off of evaporated water. You can moderately stock the tank with thin-bodied fish such as danios or small tetras or lightly stock it with thick-bodied or large fish such as goldfish, angel fish, larger cichlids or delicate species of fish. Match replacement water pH and temperature to the tank water, and add water conditioner to the new water. Slowly add the water to the tank to top off.

    • 3

      Add salt, if required for the species of fish, or fertilizer sparingly. However, never add salt to the topping off water because salt does not evaporate and can damage plants. Add fertilizer in high-density, actively growing planted tanks weekly. Add a half-dose of fertilizer every two weeks in low-growth or low-light planted tanks. In both cases, check to make sure that the plants are prospering, growing solidly, with no rotting leaves or roots, and exhibiting a vibrant appearance. Correct the fertilizer as needed based upon the plants' appearance and by testing water nutrient levels.

    • 4

      You can make small, frequent changes to the tank water in certain circumstances, such as with delicate fish or with coldwater fish such as goldfish or mountain minnows using the same methods as those described above. Remove from 10 percent to 15 percent of the water in the aquarium every three days, and replace with new water.