Many aquarists overlook the need for calcium, magnesium and the effect of a proper Kh (Carbonate hardness) in their freshwater aquarium. Kh is basically the buffering capacity of your aquarium, a Kh above 80 ppm helps prevent sudden drops in ph (You can convert dH [German hardness] ppm by multiplying your dH by 17.9). This is especially important with livebearers, goldfish, African cichlids, brackish and many other freshwater fish. The production of Nitrates (nitric acid) will slowly reduce your ph, but a proper Kh will keep a more stable ph. Another consideration of KH is that you can safely add the buffers (both freshwater and saltwater) that effect KH without sudden changes in chemistry (unless your KH is under 80 ppm already), unlike a direct ph or GH change. For this reason you do not always have to check your KH before adding buffers such as Wonder shells.

GH

General hardness (GH) refers to the dissolved concentration primarily of magnesium and calcium ions. Both Calcium and magnesium are important for proper internal osmotic processes in fish (and invertebrates). Other ions can contribute to water hardness but are usually insignificant and difficult to measure. When fish are said to prefer ``soft'' or ``hard'' water, it is GH, not the kH that is being referred to. GH will not directly affect pH although "hard" water is generally alkaline due to some interaction of GH and kH.

Calcium carbonate in your aquarium will keep a more stable Kh, while magnesium is another important element that works with calcium. A proper amount of Calcium and Magnesium in your aquarium will affect the fish health positively. Besides helping to keep a stable Kh, magnesium and calcium have been shown to increase resistance to degenerate diseases by lowering the acidity in the body. This will help with prevention of ich, fungus, and general wear and tear in your fish. The addition of antibiotics (such as Tetracycline) will lower calcium absorbtion.

Other needs for calcium:

Calcium is a vital component in blood clotting systems and also helps in wound healing.

Calcium helps to control nerve transmission, and release of neurotransmitters.

Calcium is an essential component in the production of enzymes and hormones that regulate digestion, energy, and fat metabolism.

Calcium helps to transport ions (electrically charged particles) across the membrane.

Calcium is essential for muscle contraction.

Calcium assists in maintaining all cells and connective tissues in the body.

Other needs for Magnesium:

Normal calcium balance in organs

Healthy muscles

Healthy nerve transduction

Healthy calcium balance in blood vessels

A product called a Wonder Shell will help with your calcium, magnesium, and Kh of your aquarium. Wonder Shells also come in a medicated version for control of aquarium ich and fungus. Here are a few of their attributes:

* Helps keep aquarium clear

* Maintains stable ph

* Adds necessary minerals (electrolytes)

* Removes chlorine

* Great for Goldfish, livebearers, cichlids, and more

* Contains Calcium carbonate; sodium thiosulfate; major, minor, and trace elements including magnesium sulfate. Magnesium and calcium been proven to help fish (and humans) during stress and to help prevent disease due to acid buildup in the body.