Hello Tyler. I've mentioned this multiple times: Tanks less than 30 gallons need half the water changed twice a week. Tanks 30 gallons and larger, need half the water changed out less often, once a week is ideal. The water change doesn't only depend on the number of fish you keep. The water change also depends on replenishing the minerals in the water that the fish and plants constantly remove. The nutrients that make up a healthy water environment must be freshened up every few days, so the fish and whatever else you keep has a steady supply of nutrients.
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