Water chemistry

Since fish spend their entire life in water, water is the most important thing about an
aquarium. Understanding water and its constituents will greatly help to maintain a good
aquarium. There are basically three very important aspects to the water in your aquarium:
the temperature, the pH and the levels of constituents in the water.
Most tropical fish flourish and thrive in warmer waters. Though these fish are resilient
enough to withstand a wide range of temperatures, it is seen that warmer temperatures are
best for tropical fish. As discussed earlier, having thermostatically controlled heaters are
a must if keeping tropical fish. An easy to use thermometer is also very handy. Together,
these will help you to keep a constant check on the water temperature. The water
temperature will also affect a wide range of biological and chemical processes in your
aquarium.
The pH-value is a way of measuring the alkalinity or acidity of a solution. The pH ranges
from 0-14, where 14 is the most alkaline, and 0 is the most acidic. Fresh water fish canlive in a wide range of pH but the optimum pH values are for many popular beginner
species a slightly acidic to a neutral value, 6.5-7.5.
Water hardness is another factor of importance. Water hardness refers to the amount of
dissolved minerals in your water, especially calcium and magnesium. In most cases, you
should be able to get by without manipulating the hardness of the water. Excessively soft
water can cause problems in your tropical aquarium. Adding crushed coral to extra soft
water will increase its hardness. But beware as the pH of the water will change too.
Dissolved oxygen, Carbon dioxide, Ammonia, Nitrites and Nitrates are some of the
important elements present in your water. They are decisive factors in the health of the
aquatic life within your aquarium.
The life in the aquarium depends on dissolved oxygen in the water. Gaseous oxygen is
absorbed by water. Turbulence at the surface of the water increases the absorption of
oxygen. Plants within the aquarium give off oxygen during photosynthesis, but this
oxygen is also used up quickly. Just like fish and other animals in the aquarium, plants
need oxygen for respiration and will consume a part of the oxygen that they produce.
Since all the organisms in the aquarium – including microorganisms, invertebrates and
fish – use up the dissolved oxygen quickly it is necessary to keep your aquarium well
aerated. Plants alone will not always provide enough oxygen especially, not in aquariums
with large fish populations. Unhealthy and decaying plants will even increase the demand
for oxygen in the aquarium. A simple and basic aeration or filtration system is usually
more than enough to give plenty of oxygen to your aquarium. Regular water changes,
vacuuming off fish wastes and removing any rotting plant material will also help to
increase the oxygen levels.
Ammonia is produced by the fish metabolism and excreted via the gills in and the fish
feces. Ammonia can also be produced in your aquarium when plant material is broken
down. Ammonia is highly toxic and will kill fish if the levels get to high. Nitrites are
formed in the aquarium when the Ammonia gets broken down by bacteria. Nitrites are
also dangerous to fish and unhealthy in too large quantities. Exposure to too much Nitrite
can for instance make the fish anemic and eventually kill it.
Nitrates are another nitrogen-compound and Nitrate is produces when Nitrite is broken
down by another type of bacteria. High levels of Nitrates are also toxic for fish, but most
fish species are more resilient towards Nitrate than towards Ammonia and Nitrite. You
should strive to keep the levels of Ammonia and Nitrite at zero, but low levels of Nitrates
will always be present in the aquarium and your task will be to keep Nitrate under control
rather then to eliminate it completely. Taking some easy precautions can do this. Never
overstock your aquarium. Never overfeed your fish. Never lay off changing water
partially. Never allow debris and fish waste to collect in your aquarium.