Calcite or Calcite
It is a filter medium in Calcium carbonate that corrects the pH to achieve a non-corrosive balance.
Correction of pH
One of the advantages of Calcite is its self-limiting property. When applied properly, it corrects the pH enough to achieve a non-corrosive balance.
Under normal conditions, upon contact with Calcite, acidic waters slowly dissolve calcium carbonate to raise the pH, which reduces possible leaching of copper, lead, and other metals found in typical pumping systems.
Filled in and backwash
Depending on the pH, the water chemistry and the service flow, the Calcite bed should be periodically refilled when the Calcite runs out. Because calcium carbonate neutralizes water, it will increase hardness and a softener will need to be used after the neutralizing filter. Upon contact with calcite, acidic waters slowly dissolve calcium carbonate to raise the pH, which reduces the potential for leaching of copper, lead, and other metals found in typical plumbing systems. Periodic backwashing will prevent excessive fouling, reclassify the litter, and maintain high service capacities.
Granular calcite (either marble or limestone north south) can be used both as a filter for sediment, turbidity and ferric iron and as a bed of calcium carbonate for pH correction. In general, a calcite filter will remove approximately one-third of the total ferric and ferrous iron content from a water supply.
The solubility rate of calcite is dependent on several factors. In relatively free mineral water, the average rate is 0.001 percent (about one-tenth of an ounce of calcite per gallon of water) at 77 ° F (25 ° C), but solubility increases in the presence of CO2.
Solubility is also increased by falling temperatures and increasing total pressure.
At the same time, an advantage of calcite is that the pH is not "over-corrected"; so the pH will rise evenly under proper operating conditions.
Backwash flow is very important because of the high mineral density and should be done at a minimum of 8 gpm per square foot of bed area for good performance. If iron is present, a minimum of 10 gpm should be used. Backwashing should be carried out for no less than 10 minutes to remove dirt, iron and calcite precipitates. The most common cause of pH neutralizer failures is a lack of periodic backwashing.