[phi delt reefer]

from Spectrapures site (in reference to their carbon blocks)

http://www.spectrapure.com/SYSTEM_BREAKDOWN.htm

CARBON BLOCK PRE-FILTER (2nd Stage Filter)
A Carbon Filter also has specific ratings that range from 5, 1 and 0.5. Each rating determines how much chlorine is removed in gallons of water. The 5 micron can remove chlorine for up to 6,000 gal, the1 micron for up to 9,000 and the 0.5 micron 20,000. This filter is in the 2nd stage. It removes chlorine, organics, heavy metals, trihalomethanes, pesticides and many other chemical pollutants. It will also break-up chloramines, which is chlorine bonded with ammonia ( removes the chlorine and leaves the ammonia).

(Only the 0.5 micron carbon block filter removes trihalomethanes, pesticides, volatile organic chemicals and 99.95% of giardia and cryptosporidium cysts.)

A Carbon Filter will usually lasts approx. 4-6 months ,depending on micron rating for the filters, usage and the quality of your tap water. The best way to determine when your Carbon Block Pre-Filter needs replacement is to use a chlorine test kit. Any chlorine level above 0.1 ppm will cause damage to the membrane and indicates that the carbon block filter must be changed.