Caribsea Aragonite Oolite Sugar Sand 30lb / 13.6kg Caribsea Aragamax Aragonite Oolite Sugar Sand is a calcium-rich aragonite marine substrate, packed with beneficial bacteria. Caribsea aragonite helps to create a natural biological and mineralogical balance to discourage nuisance algae growth and promote healthy fish and invertebrates. Controls Nitrate, Nitrite, Ammonia and other wastes. Unsuprassed buffering capability, helps maintain a proper pH of 8.2 without the constant addition of chemicals. Incredible surface area for water purifying bacteria, upto 100,000 square inches of surface area per pound! High in strontium, magnesium, and other trace elements eseesntial for coral growth and always silica free. Environementally responsible - not beach or reef zone collectedGrain Size : Sugar sized ideal for shallow beds and reef tank bottom cover.