Normally, it is not necessary for you to put additional dosages of FritzZyme® in your tank once the tank has cycled. Often, aquarium users place additional dosages in their tanks if they are adding new fish, are cleaning their filters or see an occasional ammonia or nitrite spike. If your aquarium is looking great and the ammonia and nitrites are at or near zero, it normally is not necessary to add additional product.
Chemical ammonia removers work by converting poisonous ammonia to non-toxic compounds. Nitrifying bacteria may not be able to utilize some of these compounds. The use of ammonia removers will only prolong the time needed to establish the biofilter. Repeated use of these chemicals may also lower the pH of the water. Nitrification will cease if the pH drops below 6.5.
U.V. sterilizers, foam fractionators (protein skimmers) and ozone generators should not be used for at least 5 days after FritzZyme® additions. This allows the bacteria time to become attached so that they will not be killed or removed by these types of equipment. Many medications will also reduce the efficiency of the biofilter.
All medications strong enough to be effective against bacterial fish diseases may affect the biological filter, whether started with FritzZyme® or not. After the disease has been eliminated, remove the medication by filtration with Fritz Super Activated Carbon. Then add FritzZyme® to re-establish the bacteria in the biofilter.
The use of any medications in either fresh or saltwater aquariums should be avoided until the biofilter has become well-established. Any medications or water conditioners containing copper, formaldehyde, malachite green and methylene blue are extremely inhibitory or lethal to nitrifying bacteria. Occasional outbreaks of protozoan parasites during this period are usually due to ammonia-related stress. Treating with one of these chemicals only adds to the problem by allowing ammonia to reach toxic levels. It is advisable to remove infected fish to a quarantine or hospital tank for treatment. Once nitrifying bacteria have become well established, they will become tolerant to low levels of copper.
Formalin is a generic term which describes a solution of 37% formaldehyde gas dissolved in water. It will kill bacteria in your bio-filter, which will lead to ammonia and nitrite spikes.
Formalin is used as a bath treatment to control external parasitic infections of fish. It is extremely effective against most protozoans, as well as some of the larger parasites such as monogenetic trematodes. Formalin effectively kills parasites on gills, skin and fins. It is not the preferred treatment for external bacterial or fungal infections. In addition, high concentrations of formalin are used to control fungi on fish eggs.
Formalin is not effective against internal infections of any type.
For more information, see the following article: http://edis.ifas.ufl.edu/vm061