All Aqua Natural gravel or substrates are 100% natural, sustainably sourced, triple washed and kiln dried. Our meticulously graded gravels and sands are the perfect natural substrates for any aquarium including planted tanks. Our high quality products create natural beauty combined with large surface areas for beneficial bacteria colonies and easy cleaning. Contains bio activated live nitrifying bacteria to either use as a primary substrate or mix with substrate for a healthy aquarium. We recommend using 1 bio-substrate bag with 4 of our dry bags to speed tank's cycling. Contains a patented blend of live nitrosomas and nitrobacter bacteria which break down and convert harmful ammonia, into nitrates. Matches dry AquaNautral Galaxy sand.