Tap water is safe to use in a planted aquarium and with fish, as long as the water has been dechlorinated and has the right water parameters. It’s important to choose aquatic plants and fish species that are suitable for your tap water’s pH and KH levels.
The term “alkalinity” refers to the sum of all bases that buffer against aquarium pH swings, with carbonate being the most frequent and important base. Carbonate hardness, or KH, only measures the concentration of carbonate and bicarbonate bases.
KH measures an aquarium’s carbonate hardness, or the degree to which it is able to buffer against pH fluctuations. GH stands for general hardness, which measures the number of dissolved calcium and magnesium ions. GH is crucial for the growth of certain fish species.
A pH between 6.0 to 7.5 will allow you to successfully grow the majority of aquatic plants. However, many less demanding plants grow well with a pH between 7.5 to 8.5, such as water wisteria, hygrophila polysperma and staurogyne repens.
High-tech tanks are characterized by their use of high-intensity lighting, artificial CO2 injection, and daily macronutrient supplementation. Low-tech tanks typically use low or medium-intensity lighting with weekly nutrient dosing and no added CO2.