The chemical abnormalities relate to the type of stones that form in the kidneys. These four types of stones and the chemical abnormalities that cause them are: Calcium Stones: people who form this type of stone either have too much of one type of three chemicals in their urine, or not enough of another.
Therefore, we recommend replacing your refrigerator's water filter typically every six months or when the gallon capacity is reached. We offer compatible replacements for Whirlpool refrigerator water filters, Kenmore, Frigidaire, Samsung, LG, Maytag and other popular refrigerator brand water filters.
Most Reverse Osmosis Filter Systems say that: 1  Pre and post filters should be changed every 6 to 12 months. 2  The membrane should be changed every 2-3 years OR if you notice a significant drop in water passing through the reverse osmosis system. The O-rings should be changed every other filter change on the pre and post filters and every change on the membrane.