Comparison Aquafilter RXRO675P vs Aquafilter RXRO675

The filter has a water purification system based on reverse osmosis.

Osmosis is the process of transition of water molecules through the so-called semi-permeable membrane — a barrier that freely passes water molecules, but retains substances dissolved in it. Usually this movement occurs from a solution with a lower concentration of impurities to a solution with a higher concentration, but there are ways to run osmosis in the opposite direction. Purification is based on this: pure water passes through the membrane, and impurities dissolved in it remain behind the barrier.

Since the separation is carried out at the molecular level, the degree of purification during reverse osmosis is very high (for example, salt water becomes fresh, not to mention the fact that the membrane does not allow bacteria to pass through). Another advantage of osmotic membranes is a long service life (see "Resource") compared to conventional filter elements: about several years, usually from 1 to 4. At the same time, reverse osmosis systems are also have disadvantages. For example, their normal operation requires a fairly high pressure, and their performance is lower than with most other filtration methods — to the point that you have to install a storage tank, which accordingly affects the dimensions. In addition, unlike other types of filtration, only about 40% of the incoming water is purified with reverse osmosis, while the rest is draine...d into the sewer along with the filtered impurities. As a result, this function is found mainly in sink filters and purifiers (see "Type"), where the quality of cleaning is crucial, and large volumes are not required.

The diameter of the pipes to which the filter is designed to be connected; indicated only for models with water connection, see "Connection". In plumbing, pipes of standard diameters are usually used, and inches are used for measurement — for example, 0.75", 1", etc. Most filters are equipped with a set of adapters for different pipe diameters, therefore, most likely there will be no connection problems, even if the initial diameters do not match. Nevertheless, it is best to choose a filter that matches your water supply in terms of fitting size — in this case, the connection is more reliable, and compliance with the claimed characteristics will be complete.

The lowest inlet water pressure at which the filter is able to fully perform its functions. Indicated for models with a connection to the water supply — directly or through a tap (see "Connection").

The design of some filters requires a certain level of inlet pressure for normal operation; if the pressure is insufficient, both throughput and overall filter efficiency suffer, and some functions are not available at all. The latter is especially true for reverse osmosis (see above). Therefore, if the minimum operating pressure is directly indicated in the filter characteristics, you should make sure that your water supply system complies with this parameter before purchasing.

Note that for filters with a booster pump, this column indicates the lowest pressure at which the filter still does not require the use of a pump; see "Pump" for details.

The highest inlet water temperature at which the filter is able to operate normally. Modern filters are conditionally divided into models for cold and hot water: the operating temperature in the first case does not exceed 40 °C, and in the second it can reach 95 °C. For more information on the importance of matching water temperature and filter characteristics, see "Purpose".

Availability of a tank in the reverse osmosis system. It provides a convenient and necessary reserve of clean water (since the filtration process itself is slow) and is installed after the membrane, before the final purification stage (post-filter). Inside the tank, there is a pressurized air compartment that allows water to be displaced when the faucet is opened. That is why the useful volume of the tank is less than the total volume, which we indicate.

The volume (size) of the reverse osmosis tank is selected based on needs and available space. The most common option is 12 liters, suitable for a family of 3–4 people.

The filter has its own pump. This feature is found mainly in two types of filters. The first is reverse osmosis systems (see above): the operation of such filtration requires high pressure, but it is not always achieved at the inlet, and a pump, usually electric, is provided to increase the pressure. The second option is tourist filters (see "Type"), where the pump is designed to draw water from natural reservoirs; they have to be pumped manually.