Ozone (Oz) consists of three oxygen atoms and is also a strong oxidizing agent. It is also used to disinfect water. As a result of the rapid and complete decomposition of ozone (Oz) to oxygen (O2) on the way from the waterworks to our apartments, ozone is no longer present in our drinking water. Many aquarists use ozone to increase their redox potential and to disinfect, and thereby reduce the number of microorganisms in the aquarium’s seawater. Ozone can be obtained using small devices sold in the shops, in which it is formed from oxygen as a result of an electric discharge. In this case, air passes through the reaction compartment with a strong electric field (several thousand volts). During the passage of air, “silent” discharges are produced, i.e. discharges without sparking, due to which air oxygen is partially converted into ozone. If the ozone formed in the apparatus immediately enters the aquarium, it will cause great damage to the fish and may even lead to their death.
In water with ozone, the fish exhibit severe stress symptoms, signs of poisoning, and general malaise appear. Already in the presence of a small amount of ozone in the water, chronic changes occur in the metabolic organs and in the blood. Elevated blood sugar, increased lymphocytes in the blood, and gill hyperplasia (epithelial growth) are the effects of ozone poisoning.
In acute poisoning as a result of a strong oxidizing effect, organic compounds (enzymes, lipids, etc.) are damaged in sensitive areas of the gill epithelium, as a result of which the gills are destroyed. The normal functioning of the gills (excretion, respiration) is no longer possible. In chronic poisoning as a result of metabolic disorders, the work of all organs is disrupted.
Ozone is very toxic! Already at a concentration of 0.007 mg / L, which lasts for 96 hours, along with the massive destruction of the gill epithelium, the entire metabolic process is disturbed. This becomes noticeable primarily through a change in the composition of the blood. So, the sodium content in the blood drops to 80%, on the contrary, the content of hemoglobin (140%) and glucose in the blood plasma (1200%) increases sharply. Therefore, the ozone content should not exceed a concentration of 0.002 mg / L.
If symptoms of acute ozone poisoning are manifested, its administration should be stopped immediately. Only then can there be little hope that fish can be saved. Most often, help comes too late.
Ozone should be introduced into the aquarium only in exceptional cases. In this case, precautionary measures must be observed: ozone should never be directly introduced into the aquarium or come from any reaction vessel. It is best to place aquarium water together with ozone in a reaction vessel to which an activated carbon filter is connected, so that with the help of activated carbon initiate the complete decomposition of ozone dissolved in water.