Desgined for planted aquariums and aquascaping, Controsand by Ultum Nature Systems is a natural substrate blended for freshwater aquariums and terrariums, Controsand is safe for fish/invertabrates/reptiles. Controsands can be used alone or in combonation, layered to create different scapes. Kona is a grey rounded pebble gravel designed for freshwater aquarium use. Konaâs deeper tones can be used as a supporting feature or to create excellent contrast. Like other Controsands, Kona can be used alone or mixed with other substrates for a custom look in planted tanks, terrariums, paludariums and more.