Thursday, November 28, 2013

What is Amonia?

Ammonia in Fish Tanks

Ammonia has no place in a healthy aquarium. Along with nitrite, ammonia is often referred to by aquarists as “invisible assassins” in the fish tank. It is a colorless waste product of fish that readily dissolves in water.

Ammonia—What Is It?

Ammonia is a compound that is made up of hydrogen and nitrogen. In fish tanks, ammonia occurs in two forms—free ammonia (NH3) and ammonium (NH4). The form which is present in the tank depends on specific environmental factors that exist inside the aquarium. The degree of toxicity suffered by tropical fish in tanks will also depend on the form of ammonia which is present.

Monday, November 18, 2013

Salt in Freshwater Aquariums

Salt in Freshwater Aquariums

Veteran aquarists know that salt is an important component in freshwater setups. Adding salt became a popular practice among aquarists during the 1990’s in an effort to prevent disease as well as promote a balanced osmotic pressure.

Important reasons for adding salt to freshwater aquarium tanks:
  • Medication 
  • Stress reduction 
  • Reduction of osmotic pressure 
  • Increase water hardness 
  • Inhibit nitrite uptake 
  • Promote the slime coat 
  • Promote wound healing 
  • Create a better environment for fish that come from brackish water 

Thursday, November 14, 2013

How to Test Water Hardness in your Aquarium and Fish Pond

How to Test for Water Hardness

Fish need specific tank conditions in order to survive. For aquarists, the need to ensure that all essential water parameters that influence water quality are continually met is of prime importance.

One of these important water parameters is water hardness. Testing your fish aquarium tank water regularly for water hardness can definitely promote the health and well-being of your fish.

There are water testing kits that you can easily order from an online aquarium store. These test kits have been designed to assess tap water and freshwater aquarium for general hardness (GH) and carbonate hardness (KH).

Methods Used to Soften Aquarium Water

Water softeners work by removing almost all the magnesium and calcium from the water.

Water-softening devices work via an ion-exchange process wherein ions that cause water hardness exchange places with sodium and chloride ions that are bound to zeolite or resin filter.

The MarinaInternal Filter i25 comes with a specially-designed Power Cartridge that provides a 3-stage filtration system—mechanical, chemical and biological. It contains a zeolite chamber where toxic ammonia is removed when water passes through the chamber.

Peat can also be used for water softening because of its ability to absorb and sequester calcium ions while releasing humic and tannic acids into the water and lowering the pH.

Other effective measures to lower water hardness include reducing the fish load, increasing filtration, increasing the amount and frequency of making water changes.

Methods to increase water hardness

  • Addition of crushed coral and coral sand
          PISCES coral sand contains calcium carbonate that can raise the water hardness and also serve as a buffer for the pH.
  • Baking Soda, Marine Salt, and Epsom Salts
Aside from raising the water hardness, adding these substances into a freshwater aquarium can also raise the pH value. Baking soda can add plenty of bicarbonate ions to the water. It should be combined with some Epsom salt and calcium chloride to increase water hardness.
  • Calcitic Gravel
Calcitic gravel can boost water hardness however it is only effective up to pH 7.5. Many aquarists add calcitic gravel in hard, alkaline aquariums to serve as a form of insurance in case aquarium condition goes awry and the pH drops dramatically.

General guidelines of acceptable General Hardness (dH) and Carbonate Hardness (KH) for different types of freshwater aquariums, tropical marine aquariums, and ponds.

Freshwater Community
African Cichlid
Freshwater Plants &
(Carbonate Hardness)
4 - 8 KH
10 - 18 KH
3 - 8 KH
10 - 18 KH
4 - 8 KH
4 - 12 GH
12 - 20 GH
3 - 8 GH
12 - 20 GH
4 - 12 GH

Suggested Level:
Reef Aquarium
Suggested Level:
FOWLR Aquarium
Average Level:
Coral Reefs
8 - 12 dKH
8 - 12 dKH
6 - 8 dKH

Wednesday, November 6, 2013

Water hardness and Fish Health

Water Hardness and Fish Health

Water hardness can have an important influence on many aspects of fish health. It has the power to influence the pH and pH stability of your aquarium water. One major effect that we have to talk about is the relationship between water hardness and fish osmoregulation.


In order to better understand what osmoregulation is, we need to tackle osmosis first.

Osmosis is a diffusion of water across a membrane from the hypotonic solution to the hypertonic solution. A solution with lower salt concentration is termed hypotonic and the solution with higher salt concentration is called hypertonic. Isotonic solution means that salt concentration in both solutions are equal. Have a look at how osmosis works in this video.

When salt concentration in the body of the fish differs from that of the external water, a concentration gradient is formed. Under this existing condition, there will be constant exchange of salt and water via osmosis to achieve equilibrium in concentration. The process of osmosis takes place on the thin membrane found on the gills of fish. Below is a figure taken from Campbell, A. Biology 1997 pg 149 regarding water balance of living cells.

When animal cell is immersed in isotonic solution, the flow of water in and out across the membrane occurs at the same rate. In this condition, the body cells are in a stable state and there is optimum function.

In hypertonic solution, the water from the cell moves to its environment leaving the cell shrivelled and may result to cell death.

In hypotonic solution, water will flow into the cell filling it like a balloon until it will burst. In plant cells, the rigid cell wall prevents bursting.


Osmoregulation is an important process to neutralize the natural forces of osmosis to maintain isotonic bodily fluids.

Being ectotherms, fishes are influenced by the conditions that exist in the surrounding water. As a result of osmosis, there is continuous flow of water into and out of the body of the fish. With this continuous water movement, the fish needs to maintain a constant concentration of its internal body fluid. This process which is involved in maintaining the concentration is called osmoregulation. Take note that the greater the difference in the concentration between the surrounding water and the body fluids of the fish, the greater will be the osmotic effect.

Since hard water is more concentrated compared to soft water, there will be lesser difference in concentration and consequently less water influx and lesser efforts undertaken for osmoregulation. When fishes work hard at osmoregulation as a result of unsuitable water hardness in fish aquarium tanks, it can eventually compromise fish health.

Watch the video below prepared by Paul Anderson, a science teacher and technology specialist at Bozeman High School. Paul explained the osmoregulation process of both fresh and salt water fish in an easy to understand manner.