Specifications

Performance & Technical Information
The performance of the Aqua-Cleer
®
/Good Water Machine
®
system can be characterized and judged by the quality and quantity of
the water produced by the system. By measuring the contaminant removal performance and flow rates of the system, its operating
status can be easily evaluated.
Factors Which Affect Performance
Performance of the reverse osmosis membrane is affected by several factors which must be considered when judging the condition
of the system. The main factors which affect system performance are pressure, temperature, total dissolved solids level, recovery
and pH.
Pressure
Water pressure affects both the quantity and quality of the water produced by the RO membrane. Generally, the more water
pressure, the better the performance of the system. Be careful not to exceed 120 psi, the maximum operating pressure of the
Aqua-Cleer system.
Temperature
The reverse osmosis process slows with decreasing temperature. To compensate, a temperature correction factor is used to adjust
the actual performance of the RO membrane filter to the standard temperature of 77°F (25°C). This allows the performance of the
unit to be accurately gauged against Culligan’s published standards. Temperature does not affect the concentrate flow rate.
Total Dissolved Solids
The minimum driving force which is necessary to stop or reverse the natural osmosis process is termed osmotic pressure. As
the total dissolved solids level of the feed water increases, the amount of osmotic pressure increases and acts as back pressure
against the reverse osmosis process. Osmotic pressure becomes significant at TDS levels above 500 mg/L (ppm).
Hardness
Hardness is the most common membrane foulant. If ignored, this relatively harmless component of feed water will plug a
membrane over time. Use of a softener will reduce the fouling effect on a membrane. If an RO system does not have access
to softened water, reduce the recovery rating (refer to page 8) to decrease the concentration of contaminants at the membrane
surface, thereby reducing the scaling potential. One way to detect too much hardness in the feed water is the presence of scale,
crystals or other precipitates at the bottom of the membrane housing. Another quick indication is the weight of a membrane
installed for a period of time. A fouled membrane (dried) will weigh significantly more than a new membrane. The increase in
weight is a result of precipitated hardness inside the membrane. To identify a plugged/clogged membrane look at the ends for
visible signs of scale build up between the wraps.
Iron
Iron is another common membrane foulant. There are a variety of types of iron, some of which cannot be removed by an iron
filter. Clear water iron can be removed more effectively by a softener. Particulate iron can be removed more effectively by a 1
micron filter. Organic-bound iron can be removed only by activated carbon or macroporous anion resin. If there is enough iron to
exceed the EPA secondary drinking water standard and softening the water is not an option and the iron is soluble, then an iron
filter is appropriate. If none of these are an option then regular replacement of membranes will have to be accepted. A iron fouled
membrane looks red at the ends and in between the wraps.
Biological Growth
Biological growth also has a fouling effect on a membrane. This water characteristic is usually diagnosed by seeing slime covering
the membrane. If a membrane with biological growth were opened the interior surfaces would be caked with this material.
Although regular sanitization helps keep this characteristic in check, some supplies, even though chlorinated, can cause biological
fouling.
Performance & Technical Information 19