Water hardness and Catfish Hatchery





TDS= Total Dissolved Solids;

The ability of water to dissolve, combine with, or suspend other elements and compounds can be helpful as a supply of necessary nutrients. Water can also be a source of trouble for the fish farmerd because it can contain chemicals that are irritants or toxic to fishes. Aside from overall stress, water quality is the most common cause of fish diseases. 

A constant level of minerals in the water is necessary for aquatic life. Changes in the amounts of dissolved solids can be harmful because the density of total dissolved solids determines the flow of water in and out of an organism’s cells. Concentrations that are too high or too low may limit the growth and may lead to the death of many fish.

A level of 400ppm or less is recommended for most freshwater fish although many softwater fish demand a significantly lower level. 

Total Dissolved Solids are also important for proper osmotic regulation, which is the relationship of water versus dissolved solids in the cells and the external environment.

The greater the amount of solids in the water versus the solids in the tissue of the fish will result in a fluid loss via the gills. 



 EC = means electrical conductivity. This is a measure for measuring the sodium concentration of a solution.


Electrical conductivity in a substance occurs when it contains sodium. For example, when you add nutrients (consisting of sodium) to water during the production of a fertiliser tank, a certain amount of electrical conductivity is created in the water.

The more sodium you add, the higher the EC will be. The EC also increases at a higher temperature.

With the help of an EC-meter you can measure this. When you treat with salt bath you could use EC to measure the necessary amount of salt to apply so u wont injure your fish.

You can use it to tell if ur water is rich enough for fish, planktons and other prokaryotes, etc to trive.

Since total dissolved solids content of a softened water is the same as that of the untreated raw water, a supply with a lower dissolved solids content must be gained in some other way. Blending of softened water with reverse osmosis or distilled water may produce the conditions conducive to aquatic breeding. 

It is critical to regulate the alkalinity & buffering capacity (pH) of the water as well

Salinity
Salinity is the dissolved salt content of water and is often ex-pressed as the parts of salt by weight per thousand parts of water by weight (ppt).

Channel catfish can breed and reproduce over a wide range of salinities.

Eggs can hatch and fry will de-
velop in waters with salinities up to at least 8 parts per thousand, but the optimum salinity for channel catfish hatchery supplies appears to be between 0.5 and 3 ppt
(500 to 3,000 ppm).


TDS to beneficial Hardness testing.

Hardness refers to the amounts of calcium and magnesium in the water and is expressed as ppm of equivalent CaCO3.

Adequate concentrations of environmental calcium are required for “hardening” of eggs and for normal bone and
tissue development of fry.

Symptoms of environmental calcium deficiency include swelling and poor Hatchability of eggs and slow development, lack of vigor, poor stress resistance, and low survival
of sac fry.

A minimum of 5 ppm calcium

hardness is required for adequate egg hatchiability and for development and vigor of sac fry. Higher calcium concentrations are desirable because calcium also protects fry from ammonia and metal Toxicosis.

All things considered, hatch-
Every water supplies should contain at least 20 ppm calcium hardness.
Calcium levels can be increased by adding a solution of calcium chloride to the water supply.

The calcium solution can be added by chemical metering pumps or by using an inexpensive
 “drip system” where a concentrated solution of calcium chloride is slowly

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