Helpful nutshell info: For new aquarium keepres

Found this in an ebay guide,
source:http://reviews.ebay.com/Cleaning-a-Freshwater-Aquarium_W0QQugidZ10000000001617516

This is geared for the newbie.

The first thing to remember about cleaning an aquarium is not to go overboard. In reality aquariums are mini sewer systems. The fish put waste into the water both solid and liquid form. This waste breaks down to produce or is ammonia.

I will briefly cover the nitrogen cycle. All over the planet, organisms are producing ammonia. This is made when proteins are broken down.

Ammonia in high enough concentration is toxic to many living organisms, esp. fish.

[Other than a freshly setup tank, there are situations which may result in a temporary rise in ammonia levels, even in a mature tank. These include:

• Filter failure, or lack of maintenance
• Use of medications
• The addition of a large number of fish at the same time
• Over-feeding
• Over-enthusiastic cleaning of 'biological' filter media.

In such circumstances, the bacterial population will need time to increase or recover to cope with the demand. If fish appear unwell, testing for the presence of ammonia should be a priority.

The total ammonia in an aquarium will be present in two forms: ammonia (NH3) and the ammonium ion (NH4+). The proportion will depend mainly on pH, and to a lesser extent temperature. At alkaline pH, more of the ammonia will be present as the more toxic NH3, while at acidic pH, more of the less toxic ammonium (NH4) will be present. Ammonia poisoning is therefore more common at a high pH


Ammonia can cause damage in some cases/sensitive fish at levels of only 0.1 ppm. There may be haemorrhaging and destruction of mucus membranes, the gills are particularly likely to be damaged, and may appear reddened. As with nitrite poisoning, fish may appear to gasp for air at the surface, and show rapid gill movement. Higher levels-ppm, can be fatal.

Basically in effect, Ammonia toxicity causes severe stress to fish making them more susceptible to disease and death. This chemical also causes damage to gill membranes and inhibits normal respiratory function. The needed, or desired concentration of Ammonia in the water is 0ppm (parts per million or 0grams/Liter)].

There are bacteria that feed on ammonia and oxidise it to produce nitrite or NO2. This is also a toxic substance to many organisms.

[The nitrite level should preferably always be 0ppm in a mature tank. A temporary rise in nitrite levels may be seen for the same reasons as listed for ammonia above. The Nitrite cycle follows on the Ammonia cycle.

In high concentrations, this can chemically mess with fish on an ugly level, basically it too can cause severe stress to the fish. It leads to respiratory hardship and a weakened immune system, which makes the fish more susceptible to disease and death.

Symptoms of nitrite poisoning include gasping and rapid gill movements, which could be mistaken for a shortage of oxygen. In extreme cases, fish can die of suffocation because nitrite binds to the oxygen-carrying component (haemoglobin) in the blood. It causes the blood to go brown, and effectively can cause a fish to die of suffocation even in oxygen rich water, because the blood can not transport the needed oxygen]

There is another type of bacteria that take NO2 and produce Nitrate or NO3. This is not very toxic. Many plants can use either ammonia or nitrate as plant food. There are many aquarium plants that will absorb ammonia directly. Also algae will do this. A cause of algae blooms (rapid increase in the number of algae) is excess fish waste. Live plants will help keep the algae in control when done with regular water changes.

[Nitrate is certainly it is far less toxic than ammonia or nitrite. It has been shown that levels of up to 1000 ppm may be required to cause death, but the effects of lower levels on long term health are not well understood. The sensitivity of different species to nitrate levels varies, and there may be long term effects on general health, growth and breeding ability

Generally, many aquarists seem to agree that keeping nitrates below 50 ppm is necessary to prevent any long-term effects on fish health, but below 25 ppm is more desirable. Remember that many fish may come from a natural environment where there is little or no detectable nitrate. Fish which have been aquarium bred for generations are more likely to tolerate nitrates]

It is hard to keep a closed system that is perfectly balanced. The planet earth is the only working model. When you change the water is are getting rid of the excess nitrates. Also if the water is evaporating from your tank there will be a slow build up of minerals and salts over time.

When vacuming the gravel you should only clean one third to half of the gravel at any one time. You want to leave the other side undisturbed to provide a source for more bacteria to colonize the areas that you just cleaned. One of the best biggest mistakes that newbie make is to clean the whole tank at once. The ammonia level might spike and kill some or all of your fish.

You also do not want to change all the water in the aquarium at once. It is important to use de-chlorinator when adding tap water to the aquarium. Most of the tap water in the country contains either chlorine or chloramine. Chloramine is a compound containing both chlorine and ammonia. Both can kill fish. It is also best to match the temperature as near as possible. Some fish are sensitive to sudden temperature change. In their nature environments the temperature changes slowly over hours or days. Salt water fish are even less forgiving since the ocean never changes temperature suddenly.

Water changes are important for fish health. All aquarium should have a partial water change every week. I would say that a 20% to 33% water change is a good thing. Most of the problems that cause fish diseases are related or be cured my changing the water. Fish living in clean water are healthier.