The quartz sand is a natural product and lime-free. With a grain size of only 0-1mm it is very fine. Available in three colors. The substrate can be sand, gravel or a mixture of both be designed. The needs of the fish must be taken into account. The average gravel should be rounded and have a grain size of Have a maximum of 2-3mm. A height of . is recommended as a gravel layer 6-8cm so that the plants can form enough roots. Amazon gravel offers fair conditions for all types of fish and their habitat and natural substrate. You can use the following formula to calculate how much gravel you need for your Aquarium need: (length x width x gravel height x 1.6) / 1000

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