Denimar Tablets (60 count). Nutrient tablets for the Nitratreductor. The bacteria within an anaerobic biofilter need organic nutrients as their energy source to remove nitrate. Denimar contains organic substances which dissolve slowly in water, and are taken up by the bacteria. If Denimar is dosed daily, high nitrate removal rates can be achieved in the Nitrate reductor. Denimar is suited for salt and fresh water aquaria. It contains no fertilizers and does not foster the growth of algaes.