Brightwell Aquatics CoraLazarus High-purity Calcium Media,20 kg. / 44 lb.Overview* High-purity natural mineral that may be employed in traditional calcium reactors, or even blended in to pre-existing aquarium substratum, to gradually increase and maintain the calcium concentration and alkalinity in marine aquaria.* Strong source of calcium, the most abundant cation by percent mass in aragonite, the mineral secreted by reef-building organisms to form skeletal material.* Through dissolution, provides calcium, magnesium, strontium, potassium, and carbonates.* Aids in increasing alkalinity to stabilize pH and encourage rapid biogenic aragonite formation.* Optimal average particle size for use in media reactors and calcium reactors.* Free of chloride and sulfate.Brightwell Aquatics CoraLazarus High-purity Calcium Media,20 kg. / 44 lb. Overview * High-purity natural mineral that may be employed in traditional calcium reactors, or even blended in to pre-existing aquarium substratum, to gradually increase and maintain the calcium concentration and alkalinity in marine aquaria. * Strong source of calcium, the most abundant cation by percent mass in aragonite, the mineral secreted by reef-building organisms to form skeletal material. * Through dissolution, provides calcium, magnesium, strontium, potassium, and carbonates. * Aids in increasing alkalinity to stabilize pH and encourage rapid biogenic aragonite formation. * Optimal average particle size for use in media reactors and calcium reactors. * Free of chloride and sulfate. Sizes 1kg | 5kg (price includes $4.00 heavy shipping fee) | 20kg (price includes $19.00 heavy shipping fee)Product code: 3557Item No. FM-BA-CLAZ20KG