Crystal quartz gravel for freshwater aquariums. Natural appearance. Free from harmful substances. Protection for bottom-dwelling fish due to rounded edges (grain size 1 - 2 mm). Light-resistant. CO2-resistant and hardness-neutral. Package size: 5 kg. Dennerle quartz gravel is a classic in the range and has been one of the best types of gravel for aquariums for many decades. The excellent appearance and perfect biological function of this water-neutral gravel are truly unique in this combination. It is lightfast and CO2-resistant, can be reused repeatedly, and retains its color even after years. The iron oxide coloring makes the quartz gravel water-neutral and guarantees it is free from pollutants. The grain size of 1 - 2 mm is ideal for bottom-dwelling fish and reduces the risk of dirt accumulating in the gaps. It is also very suitable for plants with fine root systems. The use of rounded grains significantly reduces the risk of injury to the animals in the aquarium. The very small gaps that remain provide an ideal settlement area for important bacteria. Dennerle quartz gravel does not need to be pre-washed (except for the natural white color).