Bio digest is made up of nitrifying, nitrate reducing and facultative bacterial strains selected for their ability to convert ammonia into nitrites, nitrites into nitrates and nitrates into nitrogen. Biological filtration quickly gets underway thanks to nitrifying bacteria such as nitrosamines European and nitrobacteria winogradskyi. These bacteria 50 billion in each 1ml ampoule work together with each strain finishing off the work started by the others. Some are capable of biosynthesizing nitrate reducing enzymes in aerobic conditions. This enables water to be effectively purified, nitrates and phosphates to be reduced and prevents the spread of filamentous algae. Why should the product be dosed every two weeks? Bio digest is particularly effective in the first two weeks. The speed at which the bacteria develop differs from one strain to another. Bio digest guarantees optimal purification proportions for a fortnight. If you want to speed up the purification process, you should not increase doses but instead use the product more frequently.