Free shipping on orders over $100 in the U.S., excluding Hawaii and Alaska

*Free UPS Ground shipping for orders over $100 shipped within the contiguous United States. Free shipping does not apply to shipments to Hawaii or Alaska. Products not available for shipment to Canada.

Shop for Replacements

Special Offers

Shop by Brand

WaterMaker Five RO System

Sierra RO System

Cascade Filtration System

TDS Water Quality Tester

The Nimbus Water Store is an authorized source for Nimbus residential reverse osmosis systems and genuine Nimbus replacement parts. All Nimbus products are manufactured in the U.S. and shipped direct from the factory in Temecula, California. For more information on Nimbus Water Systems, please visit www.nimbuswater.com.

Sierra

FAQs

Can the Sierra system be used on well water?
The Sierra is only warrantied for use on potable, municipal water that meets specific requirements for pressure, temperature, SDI, NTU, TDS, chlorine and pH. All of these feed water requirements are outlined in the Sierra manual. These requirements include complete removal of iron, manganese and hydrogen sulfide. Even well-managed wells may not meet these requirements and so the Sierra warranty excludes well water as a feed water source.

Can I use the Sierra system after a water softener?
Yes, the Sierra may be installed following a water softener in order to reduce the concentration of sodium ions which have been exchanged for hardness ions in the softening process.

Can the Sierra be used on very cold feed water?
Yes, but your production rate might be lower than the rated flow. Cold water temperatures can significantly decrease the flux rate of a reverse osmosis membrane. Most reverse osmosis membranes are rated at 77°F.

When should I change the membrane cartridge in my Sierra?
We recommend a yearly change-out for the membrane cartridge on your Sierra. This ensures that you will have consistently high quality drinking water. In some cases, depending on the characteristics of your local tap water, you may need to change the filters earlier or later.

The best way to determine when to change out the filters is to test your water with the HM Digital TDS Water Quality Tester. This meter can measure the conductivity of the TDS in both your incoming water and the water from your Sierra faucet.

Please use the link to the Nimbus TDS calculator to find out the TDS reduction percentage. We recommend the membrane cartridge be changed whenever the TDS reduction drops below 85%.

How often should I test the TDS in the Sierra product water?
We suggest monthly testing. We suggest monthly testing. Please watch our TDS video for a quick tutorial on how to use the TDS Water Quality Tester.

Once you know the starting point for your specific local water, testing can be performed in seconds. Fill a small container (drinking glass) with purified product water from your Sierra faucet, place the digital TDS Water Quality Tester in the water and press the test button. Note the reading. Empty the container and fill with regular tap water. Place the digital TDS Water Quality Tester in the water and press the button. Note the reading. Please use the link to the Nimbus TDS calculator to find out the TDS reduction percentage. We recommend the membrane cartridge be changed whenever the TDS reduction drops below 85%.

How is the TDS reduction percentage calculated?
The formula for TDS reduction is:

((TDS in feed water - TDS in product water)/TDS in feed water) * 100 = % reduction
((500 ppm - 18 ppm)/500 ppm) * 100 = 96%

Total Dissolved Solids (TDS) is expressed in parts per million (ppm). TDS meters measure only the mixed salts ions as ppm. The ppm rating is a measurement not only of water quality but also of membrane integrity. A properly functioning RO system will deliver 94% to 98% reduction of TDS at the start of its lifetime. When the TDS rejection goes down to 85% it is an indication that the membrane should be replaced.