Aquarium Plants

Under the influence of sunlight, plants and only plants have the ability to manufacture their own food. These green plants combine water and carbon dioxide to form sugars in a process known as “photosynthesis.”

During this process, free oxygen is released in excess of that used by the plant for respiration. This occurs only under the influence of bright light. At other times, the plant breathes normally, consuming oxygen and giving off carbon dioxide. Photosynthesis occurs only when the plant in light is healthy and growing.

Light, then, is essential to your aquarium so that the plants will grow properly and give off oxygen and consume carbon dioxide. The “wonder material” that regulates the food manufacturing process is chlorophyll - the material that gives plants their green color.

There is a good deal of controversy concerning the amount of oxygen that the aquarium plants actually supply for fishes to use.

It should be remembered that water can dissolve only a certain amount of oxygen; any excess oxygen is therefore released at the surface. It is not stored in the water for later use as the fishes require it. Carbon dioxide is released and oxygen is taken into the water. The process can be hastened by bubbling stream of air through the water. This tends to agitate the water and increase the area exposed to the surface in proportion to the amount of circulation engendered. Manual stirring of the water serves the same purpose, but it is not so convenient a method as the mechanical one.

The greater the area of the exposed-to-air water surface, the faster oxygen will be taken in and carbon dioxide released. The greater the air surface, the more fishes can be kept in a given volume of water. You do not really increase the capacity of the fish tank to hold fishes simply by raising the height of the water in the tank. You must also increase the other dimensions in proportion.

Probably the same number of fishes could be maintained in a bare aquarium as in one with plants. Then, you may ask, why bother with aquarium plants? Well, plants serve many functions besides the disputed one of oxygenating. The principal function is an esthetic one: there would not be much beauty to a tank without plants. They provide an excellent background against which your colorful fishes will display themselves to best advantage.

What is a water hardness testing kit?

A water hardness testing kit is a kit containing ingredients for measuring the amount or number of grains per gallon of the dissolved salts of magnesium or calcium present in the water.

There are two types of kits available. The first involves the use of three chemicals which are added in succession to a sample of water to be tested. The number of drops of the last solution required to change the color is a measure of grains of hardness per gallon. The second type of kit makes use of the fact that soap will not lather readily in hard water. Drops of a standard soap solution are added to a sample of water. The number of drops required to produce lather equals its hardness in grains per gallon.

A rough idea of the hardness can be gained by washing your hands in some of it. Soft water lathers readily.

Like pH, there is a good deal of controversy as to the practical importance of water hardness. Most fishes can certainly stand extremely hard water if they are gradually accustomed to it. Many fishes will breed much more readily in soft, slightly acid water. There are chemical water softeners which will remove the calcium and magnesium salts from water. There are also water demineralizers available. These remove all the dissolved minerals from the water, leaving it almost as pure as distilled water.

Neither of these should be used on water while the fishes are present. Fishes cannot live in distilled water. To avoid overdoing it, when your water is too hard, make changes carefully. Soften some water separately. Dilute your aquarium water by adding this water to it and testing frequently. The amount to add depends on the degree of hardness you start with and the degree of hardness required. A hardness of 3 to 9 grains of hardness is the most satisfactory, although as stated before most fishes can stand water much harder than this, if the change to it is gradual.

Hardness is frequently measured as parts per million, abbreviated as p.p.m. Divide the number of parts per million by 17.1 to find the grains per gallon.