Standard filter units are designed to store away as many contaminants as possible. To do that they often use multiple stages of filtration. This means that the dirt never leaves your drinking water stream. It just keeps collecting there until you change the multiple expensive filters. Marigold gets the dirt out of the system before it ever has a chance to build up. The Marigold system also flushes out stale water so it is not the first water going right into your glass. The dirty little secret about Reverse Osmosis (RO) systems is that they waste nine or more gallons of pre-filtered water for every one gallon of drinking water produced. That is wasteful as well as expensive. RO is great for a laboratory, but it removes too much. It removes healthy minerals that makes your water taste good, leaving you with tasteless, soft tasting water. RO water is also warm and stale. The complicated process is so slow that they have to store your drinking water in a room temperature tank, getting stale and growing bacteria slimes inside the warm metal tank. Not what you want for drinking water. Marigold is constructed of all lead free and food grade materials. The 5 micron filter removes greater than 95% chlorine. Even though a Marigold system will last longer than other systems due to the regular flushing out of solid contaminants, always replace your filters every 6 months for optimal taste and flavor. All carbon block elements of a given micron size and made with high grade carbon will remove the same level of chemicals like chlorine and rotten egg flavor, no matter the crazy array of chemicals actually tested for. More testing does not equal higher performance. Some are artificially rated higher and claim to last forever, but then they are barely effective at the end. The taste and cleanliness of your drinking water is worth the pennies a day to just replace the element every six months.