Mastering Freshwater Aquarium Ecosystems
Bookmark This Page

Water Testing (Cont.)

Carbonate Hardness (KH)

Carbonate Hardness or KH, measures the alkalinity. KH refers to the concentration of bicarbonate (HCO3-) and carbonate (CO3--) dissolved in water. Carbonate Hardness measures the buffering capacity of the water. The higher the concentration the more resistant the water is to pH fluctuation. This test kit is usually targeted for marine (saltwater) aquarium hobbyist, but should also be considered by freshwater hobbyist that want to keep Lake Malawi, Lake Tanganyika, and Central and South American livebearers.  Many carbonate hardness test kits measure in degrees of hardness, based on a German scale and is represented by “dKH” or “KH” acronym. If the test kit you use tests on a dKH scale, you will need to multiply the results times 17.86 to convert to ppm.

A system with a higher KH level can help reduce the pH lowering effect nitrate has on the aquarium ecosystem.

Total Dissolved Solids (TDS) Meter

Total Dissolved Solids meter will check the water for all elements dissolved in the water (ie. salt, calcium, carbonate, bicarbonate, magnesium). This meter a valuable tool in figuring out exactly how much in parts per million of dissolved solids have been added when adjusting the water chemistry. You can usually find these meters for less than $30.

TDS Meter

A TDS measures all the elements dissolved in the water. It is a good instrument to use for checking the TDS effluent from water softening systems and also checking how much TDS has increased after adding chemicals to the aquarium water.

TDS meters are also used to measure the effluent of reverse osmosis filtration systems to determine if a membrane needs to be replaced.  If the TDS is elevated beyond an acceptable value, it is then time to replace the membrane.

Aquaworld Sponsor