A rated figure is a reference point, not a site guarantee. Here is how to compare specifications fairly.
What a rating means
Flow and output ratings are measured under defined test or operating conditions, such as pressure, temperature and feed water quality. When site conditions differ, results can differ too.
Factors that change performance
- Pressure: lower pressure can reduce flow and, for RO, output.
- Temperature: RO output generally falls in colder water.
- Feed water: higher sediment or dissolved solids loads can shorten cartridge and membrane life.
- Contact time: adsorption depends on how long the water is in contact with the media. The ADWG notes that contact time affects removal in carbon treatment [1]. That guidance is about treatment plants, not cartridge ratings, but the principle is why a higher flow is not automatically better.
- Cartridge age: performance changes as media loads up.
Evidence boundary
The ADWG reference below supports the contact-time discussion only. The pressure, temperature and RO points are general selection considerations, not performance figures derived from that reference. Obtain model-specific operating limits and test data for your feed water and application.
Comparing specifications fairly
When comparing two products, check that the figures were measured under comparable conditions. A higher number measured under different conditions is not a like-for-like comparison.
Key buying implications
- Ask for the conditions behind each rated figure.
- Compare models under the same pressure, temperature and feed water assumptions.
- Size for peak demand and allow for seasonal temperature.
- Plan for consumables, because performance changes over the cartridge's service life.
Talk to us
Share your site pressure, demand and water source and we can discuss suitable options. Send an enquiry.