CEI's GreensandPlus is a purple-gray granular filter media that is made by bonding silica sand with a manganese dioxide coating. GreensandPlus is used to remove soluble iron, manganese, hydrogen sulfide, arsenic, and radium for water supplies, and eliminate odors.
Soluble iron and manganese are oxidized and precipitated as they come in contact with the GreensandPlus granules. Hydrogen sulfide gas is reduced by oxidation into an insoluble sulfur precipitate. These precipitates are then filtered (mechanically strained) out of the water by the filter bed. Once the filter bed is full of these oxidized particles, it can be cleaned by simply backwashing or flushing them away.
GreensandPlus from CEI is the modern upgraded version of the original Greensand formula. The difference between GreensandPlus and the original Greensand is in the substrate that forms the core of the media and the method by which the manganese dioxide coating is attached to that substrate. GreensandPlus has a silica sand core and the coating is fused to it while Manganese Greensand has a glauconite core and the coating is ionically bound to it. The GreensandPlus silica core is significantly harder than it's predecessor's allowing it to have a much longer service life.
The silica sand core of GreensandPlus allows it to better withstand operating conditions in waters that are low in silica, TDS and hardness without breaking down. If you are currently using manganese Greensand and are feeding sodium aluminate, you will likely be able to eliminate the aluminate feed by switching to GreensandPlus. Also, GreensandPlus can withstand higher operating temperatures and higher differential pressures than can manganese Greensand. The higher differential pressure may allow for a longer run length, but if nothing else, it allows for larger operational margin of error.
GreensandPlus can be used as an exact substitute for manganese Greensand as it has the same effective size, uniformity coefficient, density, weight, capacity, service flow rate, backwash and pressure drop curve. It can be used in CR and IR applications and requires no changes in backwash rate or times or chemical feeds. Greensand has received the WQA Gold Seal Certification for compliance with NSF/ANSI 61.