Guide category
Water Quality Guides
Read about the nitrogen cycle, ammonia, nitrite, nitrate, pH, alkalinity, hardness, and carbon dioxide. Use the guides to understand test results and connect individual measurements with overall water quality.
Water Quality reference library
Water quality
Aquarium KH and Alkalinity
Aquarium KH and alkalinity both describe water's resistance to acid-driven pH change, but routine KH titration often estimates broader acid-neutralizing capacity. In freshwater, KH is common practical shorthand; reef systems usually discuss alkalinity in dKH, meq/L, or ppm as CaCO3.
Water quality
Aquarium Ammonia
Ammonia is the first inorganic nitrogen product generated as proteins and other nitrogen-containing waste are broken down. It is both a normal input to the nitrogen cycle and a toxin when it accumulates.
Water quality
Aquarium Carbon Dioxide
Dissolved CO2 is one part of aquarium gas balance and carbonate chemistry. It supplies carbon for photosynthesis, affects pH quickly, and must be kept in balance with oxygen and animal respiration.
Water quality
Aquarium General Hardness (GH)
GH is a measure of mineral hardness, dominated in aquariums by calcium and magnesium. It does not show buffering capacity, carbonate content, pH, or every dissolved solid in the water.
Water quality
Aquarium Nitrate
Nitrate is the relatively stable oxidized nitrogen product that commonly accumulates after ammonia is converted to nitrite and nitrite is converted to nitrate.
Water quality
Aquarium Nitrite
Nitrite is the middle measurable stage of conventional aerobic nitrification: ammonia is oxidized to nitrite, then nitrite is oxidized to nitrate.
Water quality
Aquarium Nitrogen Cycle
The aquarium nitrogen cycle is a network of microbial and biological processes that moves nitrogen from organic waste into ammonia, nitrite, nitrate, living tissue, nitrogen gas, or exported material.
Water quality
Aquarium pH
pH is a central water-chemistry measurement used to describe acidity and basicity. Because the scale is logarithmic, pH 6 has ten times the hydrogen-ion activity of pH 7 and one hundred times that of pH 8.
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