Oxygen and ammonia are the two most important parameters in aquaculture. The oxygen is relatively easily controlled,
but the ammonia is much more difficult. Ammonia, the un-ionized form of ammonia (ammonia gas) is produced from the
gills and urine from the fish as well as from the bacterial decomposition of the unused food and fecal material. Fish utilize
the nitrogen component of digested proteins, the amino group (NH2) to build new proteins. However, when they utilize the proteins for energy, they cannot metabolize the nitrogen, and the amino group is split off as ammonia gas.  Ammonia gas solubilizes readily in water to form ammonium ion. Ammonia is toxic, and it reduces the ability of the hemoglobin in the
blood to hold oxygen. Additionally, ammonia damages the gill structure further impairing the fish in getting oxygen.

There are three ways to reduce ammonia in the water. First would include mechanical filtering of unused food and fecal material. Although sand and charcoal have been used extensively, zeolite is much more effective. It has a nominal rating of 3 to 5 microns (sand is typically 20 microns), it loads 2 to 3 more times the particulate load of sand, and it reduces the number
of backwashes (see usage document on water filtration). Second would be the use of a biological filter in which bacteria mineralize the organic nitrogen compounds. The process can be aerobic or “nitrification,” or anaerobic or “denitrification.” Nitrification is the most popular, and it involves the oxidation of ammonia to nitrite and then to nitrates by autotrophic bacteria (Nitrosomonas and Nitrobacter). The huge surface area of BRZ™ makes it an excellent host for bacteria. Third, the ammonia can be chemically filtered by clinoptilolite. A zeolite filter system can be used to mechanically remove food wastes and fecal material. It also removes the ammonia and becomes a host for aerobic bacteria that eat the ammonia. As such, it becomes all three filter systems in one if properly applied.

NOTES ON THE USE OF CLINOPTILOLITE IN AQUACULTURE

• The ammonium promotes the growth of algae in the pond or tank and the algae will grow on the BRZ™ where they
  utilize some of the ammonium. However, the algae on the BRZ™ will inhibit the absorption of the ammonium into the BRZ™. The algae must be washed off to accelerate the adsorption of the ammonium.
   

• Excretion of ammonia by fish increases with the activity of the fish, an increase in the temperature, and an increase
  in the feed ration. A rise of 13 degrees F can cause a 10-fold increase in the rate of excretion.
   

• The percentage of ammonia gas in solution increases with an increase in temperature.
   

• A reduction of dissolved oxygen (DO) increases the acute and chronic toxicity of ammonia.
   

• The toxicity of ammonia decreases with an increase of salinity up to 30% sea water (9 % salt).
   

• Adsorption efficiency of BRZ™ is unaffected by water temperature.
   

• Adsorption efficiency of BRZ™ decreases in water of low pH.
   

• Adsorption efficiency of BRZ™ decreases as water hardness increases. Other cations such as Ca, Na, Mg, and K compete more effectively than ammonium for the exchange position. Optimum efficiency occurs when the hardness is less than 44 mg/l.
   

• The effective depth of penetration for ammonium into BRZ™ is about ½ inch. As a result, smaller granules are more effective than larger granules. Too many fines increase the turbidity, however.
   

• BRZ™ will reduce ammonia in proportion to the amount of BRZ™ used.
   

• BRZ™ is typically not used in seawater due to the high hardness and the amount of sodium. In seawater, BRZ™ has approximately only 5% of the capacity that it has in fresh water. Much more massive amounts of BRZ™ must be used in seawater that is typically not economic.
   

• Ammonium loaded BRZ™ can be regenerated by using a saline back wash solution followed by a rinse cycle.
   

• Alternatively, aerobic bacteria, algae, or plants can be used to regenerate the BRZ™.
   

RECOMMENDED USES OF ZEOLITE FOR AQUACULTURE

 

• DECORATIVE ROCKS. -- Decorative rocks can be placed in ponds, aquariums, streams, fountains, and other tanks. Although these can be large in size, the effective penetration is only about ½ an inch. Consequently, BRZ™ larger than 1 inch diameter looses its effectiveness as a chemical or chemical/biological filter.
   

• MECHANICAL FILTRATION. --   BRZ™ makes an excellent mechanical filter media for unused food and fecal material or aquaculture ponds.
   

• CHEMICAL FILTRATION. --   BRZ™ is an excellent chemical filter for ammonium as well as for certain heavy metals by virtue of its cation exchange capacity.
   

• MEDIA FOR BIOLOGICAL FILTRATION.—the tremendous surface area and irregular surface of BRZ™ makes it a perfect media for biological colonies of aerobic bacteria. In effect it becomes a chemical/biological filter.

 

BRZ™ CONTROL OF AMMONIUM IN TROPICAL FISH BOWL - OCTOBER 2003

 

OBJECTIVE:  This test is designed to test the effectiveness of ammonium reduction in a aquarium with one Beta fish using two different zeolites: BRZ™ zeolite, and Brand X.

 

PROCEDURE:
 

• 4 small fish bowls were prepared and filled with water to study 3 groups of Beta fish.
   

• 1 fish was placed in each of four bowls designated the “control group” with no  zeolite.
   

• 1 fish was placed in each of four bowls containing a 0.3 oz rock of zeolite screened at 1” x ¾” and designated “Brand X” zeolite.
   

• 1 fish was placed in each of four bowls containing a 0.3 oz. rock of Bear River zeolite screened at 1” x ¾” and designated “BRZ™.”
   

• The water was static. There were no pumps or aerators.
   

• All fish were fed two times per day 0.03 grams of food.

 

RESULTS:  The results are in ppm ammonium.

Bowl              Day 1             Day 2             Day 3             Day 4             Day 5

      Control Group

 

1                      0                      0                      0.5                  1.0                  2.0

2                      0                      0                      0.5                  1.25                2.0

3                      0                      0.25                1.0                   1.0                  2.0

4                      0                      0.25                1.0                   1.0                  2.0

  BRZ™

 

1                      0                      0.25                1.0                   2.0                  1.5

2                      0                      0                      0.5                  1.25                1.5

3                      0                      0.25                1.0                   1.5                  1.0

4                      0                      0                      1.0                   1.25               1.5

Brand  X

1                      0                      0                      1.0                  1.25                1.5

2                      0                      0                      1.5                  1.75                2.0

3                      0                      0                      1.5                  2.0                  2.0

4                      0                      0.25                 1.0                 1.5                   2.0

Averages

Control         0                      0.1875           0.75               1.3125            2.375

BRZ™           0                      0.125             0.875             1.5                   1.375            

Brand X        0                      0.125             1.25               1.625               1.875

 

COMMENTS:

• Agitation of the water would have brought more ammonium in contact with the zeolite,
  and it would have been more effective.
   

• Smaller particles of the zeolite would have been more effective. One quarter inch is penetrated
  fairly fast, but greater depths of penetration in the zeolite are slower.
   

• The annual market for Betta fish and related supplies is $150,000,000 in the United States.