A set for water quality management. Tetra Test Paper Set of 3 for Both Freshwater and Saltwater. Features: Tetra Test Test Paper NO2-(Nitrites). A test paper that allows you to quickly check the concentration of nitrites. Simply dip the test paper into water to quickly check the concentration of nitrites. The leftovers of fish feces and feeds become harmful ammonia in the aquarium, and the function of bacteria changes into nitritic acid which is very harmful to fish. It is important to maintain the nitrite concentration of less than 0.8 mg/l (0.8 mg/l). (Tetra Test Paper NO3-(Nitrate) A test paper that can quickly check the concentration of nitrates. Simply dip the test paper into water to quickly check the nitrate concentration. The leftovers of fish feces and feeds become harmful ammonia in the aquarium, and the function of bacteria changes from the nitrous acid (salt), which is highly harmful to the fish and it also transforms into nitric acid (salt). As many nitrates, the final product of this process, it will inhibit the growth of aquatic grass and affect the health of the fish, and also produce unpleasant algae. The ideal nitrate concentration is less than 10 mg/l but it is an acceptable value of up to 25 mg/l. (Tetra Test Paper pH (Pacher) A test paper that can quickly check the pH values. Simply dip the test paper into the water to quickly check the pH values. All aquatic organisms such as fish, aquatic weeds, and microorganisms are highly sensitive to significant changes in pH value, and it is important to breed in aquariums with the appropriate pH value for each one. ● Generally, freshwater fish are breed from pH 6.5 to 8.5, saltwater fish are breed from pH 7.8 to 8.0. Set Contents: Tetra Test Paper NO2-(nitritite) x 24 times; Tetra Test Paper NO3-(nitrate) x 24 doses; Tetra Test Paper pH (pacher) x 24 doses