Reverse Osmosis SystemSKU CQE-RO-00112

Thunder Ultrafiltration/Reverse Osmosis Under Sink Water Filter | 4000M | 17 Stages of Filtration

$560.85

Warning: Although a leak detector/flood-prevention valve is optional with your purchase, it is highly recommended to avoid property damage. Due to numerous unpredictable circumstances including installation errors, flood-damage is subject to occur without a leak-detector valve. Including a leak-detector will allow the water system to be flood-proof.

Read more

Before you buy

Buying guide

Never think about replacements

Adds spare cartridges to this order, then sends fresh ones on the schedule shown. Cancel anytime.

  • Shop Pay
  • Apple Pay
  • Google Pay
  • Visa
  • Mastercard
  • American Express

Made in USA

Shipping

Free shipping on residential orders over $150 within the lower 48 US states.

Order by 3:00 PM Eastern on a business day and most filters, cartridges and smaller items leave our facility that same day. Standard residential systems ship within 1 to 2 business days, and whole house, custom and specialty systems typically within 3. So far in 2026, 95% of our orders have shipped within one business day and 99% within five (based on an internal review of our order records).

Once shipped, standard delivery typically arrives in 3 days to the Southeast, Northeast and Southwest, and in 4 days to the Midwest and the West. Need it sooner? UPS 2nd Day Air and Next Day Air are available at checkout for eligible products. Systems that ship by freight can take longer and may need a delivery appointment.

Lifetime support

Our team answers questions about products, orders, installation, troubleshooting and replacement parts.

Phone: 770-951-5600 or (800) 934-0051

Email: help@crystalquest.com. We reply within 24 to 36 hours.

Live chat during business hours

Hours: Monday to Friday, 9:00 AM to 5:00 PM Eastern. We observe U.S. federal holidays.

Warning: Although a leak detector/flood-prevention valve is optional with your purchase, it is highly recommended to avoid property damage. Due to numerous unpredictable circumstances including installation errors, flood-damage is subject to occur without a leak-detector valve. Including a leak-detector will allow the water system to be flood-proof.

Description

Water Travels Through 17 Stages of Filtration:  

STAGE 1 - Water travels through a 5 micron solid carbon cartridge for removing volatile organic carbon compounds (VOC's), insecticides, pesticides and industrial solvents and traps particles larger than 5 micron including sediment, silt, sand and dirt. It also helps to extend the life of the system.

STAGE 2 - Water passes through a 0.020 micron Ultrafiltration (UF) membrane. Ultrafiltration (UF) is an important purification technology used for the production of high-purity water. UF is effective for the removal of colloids, proteins, bacteria, viruses, parasites, protozoa and pyrogens (e.g., gram-negative bacterial endotoxins), other organic molecules larger than 0.020 micron, and most other water contaminants known today. 

STAGE 3 - Water flows through pre one - micron filter pads (1 micron equals 1/25,000th of an inch), which removes suspended particles such as silt, sediment, cyst (Giardia, Cryptosporidium), sand, rust, dirt, and other undissolved matter.

STAGE 4 - Water passes through granulated activated carbon (GAC). GAC is universally recognized and widely used as an effective adsorbent for a wide variety of organic contaminants, such as chlorine, chemicals linked to cancer (THM's, benzene) pesticides, herbicides, insecticides, volatile organic compounds (VOC's), PCB's, MTBE's and hundreds of other chemical contaminants that may be present in water, bad taste, and odors from your drinking water. 

STAGE 5 - Water flows through the ion exchange resin, reducing heavy metals such as lead, copper, aluminum, and water hardness.

STAGE 6 & 7 - Water flows through 2 beds of Eagle Redox Alloy®(Oxidation/reduction process) media made of a special high-purity alloy blend of two dissimilar metals - copper and zinc. Representing a new and unique way of water processing medium which by its natural process of electrochemical oxidation/reduction and adsorption action reduces and/or removes many unwanted contaminants from water. It is a major advancement in water treatment technology that works on the electro-chemical and spontaneous-oxidation-reduction (Eagle Redox Alloy®) principles. Chlorine is instantaneously and almost inexhaustibly oxidized.

Iron and hydrogen sulfide are oxidized into insoluble matter and attach to the surface of the media. Heavy metals such as lead, mercury, copper, nickel, chromium, cadmium, aluminum, and other dissolved metals are removed from the water by the natural process of electrochemical process. They are attracted to the surface of the media, much like a magnet. The media inhibits bacterial growth throughout the entire unit. 

STAGE 8 - Water flows through another one-micron filtration pad for further reduction of undesirable particles. The end result is a great reduction or elimination of a wide variety of contaminants.

STAGE 9 - Water passes through a CRYSTAL QUEST® reverse osmosis membrane, which removes and filters particles as small as 1/10,000 of a micron as most inorganic chemicals (such as salts, metals, minerals) most microorganisms including cryptosporidium and giardia, and most inorganic contaminants. 

STAGE 10 & 15 - Water flows through another one - micron filter pads (1 micron equals 1/25,000th of an inch), which removes suspended particles such as silt, sediment, cyst (Giardia, Cryptosporidium), sand, rust, dirt, and other undissolved matter.

STAGE 11 & 12 - Water flows through another bed of media made of a special high-purity alloy blend of two dissimilar metals - copper and zinc. it is a major advancement in water treatment technology that works on the electro-chemical and spontaneous-oxidation-reduction (REDOX) principles. Chlorine is instantaneously and almost inexhaustibly oxidized.

STAGE 13 - Water flows through another ion exchange resin, reducing heavy metals such as lead, copper, aluminum, and water hardness.

STAGE 14 - Water passes through granulated activated carbon (GAC).

STAGE 16 - Water passes through an Ultraviolet Water Sterilizer System manufactured with axial flow reactors in 304 stainless steel. The hard glass germicidal lamps provide an economical way of treating water requiring a 99.99% reduction of bacteria and virus and protozoa. This process is accomplished without adding any harmful chemicals to your drinking water. CRYSTAL QUEST® Ultraviolet Water Sterilizer System is the most ecological way of treating your water.

STAGE 17 - Water travels through a 0.20 micron Ultrafiltration (UF) membrane. Ultrafiltration. UF is effective for the removal of colloids, proteins, bacteria, viruses, parasites, protozoa and pyrogens (e.g., gram-negative bacterial endotoxins), other organic molecules larger than 0.20 micron, and most other water contaminants known today.

Features 

  1. 100 Gallons Per Day
  2. 6-stage Filtration Cartridge, post membrane cartridge, one-micron filter pad, ERA-6500®, ERA-9500®, GAC (coconut shell), ceramic ball resin, and another one-micron pad.
  3. Ultrafiltration
  4. Ultraviolet

Comes with a complete installation kit that includes a European lead-free long-reach designer faucet, CRYSTAL QUEST® 3.2 gallons stainless steel pressurized holding tank with a polypropylene inner liner and a 2.0 gallon capacity, all interconnecting color-coded tubing, filter cartridges, Ultrafiltration membrane, RO membrane, wrenches, and installation hardware.

Optional exchange filter cartridges for FLUORIDE, NITRATES, ARSENIC and other water contaminants ARE AVAILABLE!

Please Note:  When considering installation, if current under sink plumbing is hard copper tubing the saddle valve would be used; for flex tubing the T-valve would be required. While ordering a prompt will require that an installation valve be specified in order to progress through the order entry screen.

 

Please Note The Following:

  • When considering installation of an undersink unit: if current under sink plumbing is hard copper tubing the saddle valve would be used; for flex tubing the T-valve would be required. During the ordering process you will have a choice of which installation valve you prefer.
  • The influent waters psi will have a direct effect on GPD or gallon per day production. The RO is designed to work in a psi range from 35-60 with 60 being optimum. If your water pressure is low or you have a high TDS please consider a system manufactured with a pump.
  • Units are manufactured standard with 110v electrical outlet but are also available in 220v if requested.

C Series

The Thunder C Series uses a Granulated Activated Coconut Shell Carbon (GAC) Filter Cartridge, post membrane cartridge, to remove volatile organic carbon compounds (VOC’s), insecticides, pesticides and industrial solvents.

M Series

The Thunder M Series uses a 6-stage Filtration Cartridge, post membrane cartridge, one-micron filter pad, ERA-6500®, ERA-9500®, GAC (coconut shell), ceramic ball resin, and another one-micron pad.

P Models

P Models also have a pressure pump. Please consider these models if you have low water pressure.