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The MERO 100 GPD, 4 Stage RO/DI is designed and constructed to be the best choice for residential reef enthusiasts, service companies and local aquarium stores.  Every user has different needs and demands so ME allows for customization via many options to meet the needs for top off, new Seawater makeup, and Freshwater drinking systems.
The MERO is offered with a standard 100 GPD flow rate with option to increase to 300 GPD. Also standard is a double probe TDS Meter so we can monitor entire system performance at a touch of a button.  The MERO comes standard with a no rust black bracket and hardware; white is a free option.  ME feels we have designed the best possible units available; however if you need further customization let us know.

This Item Can Be Special Ordered – Please give us a call to order it 954-927-9300

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Included with every Advanced MERO 4 Stage RODI system 

Premium 1 micron Sediment Filter 10 inch
Double probe TDS Meter–used to monitor the condition of the TFC membrane and DI cartridge.
NSF Food Certified GAC activated carbon packed in refillable cartridge
Drain ball valve custom designed to rinse GAC
100 GPD High Quality TFC RO Membrane (made in USA)
Mixed Bed Color Indicating Zero TDS DI resin packed in refillable cartridge
Black Heavy Duty no rust Aluminum Mounting Bracket and Black canister tops, (white available)
Quick Connect Fittings standard
1/4″ Hose Bib Adapter for incoming water
10″ Canister Filter Wrench for easy filter removal (hand tighten only)
6 feet of supply tube, drain tube and product tube (blue,yellow,black)
MERO Instruction manual
Pressure gauge kit installed
Ball Valve Flush Kit installed (flushing membrane extends membrane life and performance)
Hydraulic Automatic shut off switch and check valve installed
Every MERO system is hand built in the USA. Providing you the highest quality.
All  units are pressure checked at the factory to confirm fittings are sealed with no leaks
One Year warranty

MERO ADVANCED systems come with many options listed above making it a very complete and advanced system that is ready to use.  Some people have different needs so the following additions are available.  Also see ChloraMEno packages if you have chloramine in your city water.

Available Options

Black Color is Standard; White is available

GPD– our standard is 100 GPD ; 200, and 300 GPD available

Additional DI Resin canister–can be added to have Dual DI canisters (One canister is standard)
Some like to run dual DI canisters to lengthen replacement time.

Booster Pump Kit-   If city water pressure is below 40 psi a Booster kit may be needed to increase membrane performance.   Check the included pressure gauge to monitor pressure

Drain saddle – used so that waste water goes down sink drain.  PVC drain pipe only

Under sink inline adapter – 3/8 Female x 3/8 Male Thread with Quick Connect Fitting for 1/4 inch Tube Fits into Most Undersink Hoses.

Drinking Water Kit–Bladder Tank with shutoff valve, 3rd Faucet, Ice Maker Tee, Choice of adapters


Operating Pressure: 45-85 PSI
Optimal Input Water Temperature: 70-77° F (21-25° C)
Output Rating: Output of MERO  RO/DI systems are measured with a water pressure of 50 PSI, 75° F water and an input TDS of 110.


                                                      MERO 4 Stage RODI WATER FLOW SEQUENCE

STAGE 1 CANISTER (GAC). Starts with incoming city water passing through TDS Probe 1 indicating how much dissolved solids are in your city water.  The first canister is full of granular activated carbon (GAC), which is NSF Certified for food and beverage use.  GAC removes chlorine, organics, and other chemicals from the water.  It does not remove chloramine which may be in your city water.  Check with your city’s water department as every city has different levels of chlorine and chloramine.  If your city water is high in chloramine then we recommend the MERO ChloraMEno unit, which is designed to remove chloramines.  Reducing chlorine is also important for extending RO Membrane life, as membranes are not chlorine tolerant.

Flush kit after GAC   GAC releases dust and particles, especially when a cartridge is refilled.  To avoid pushing dust into the next chamber we have added a Flush Valve kit to rinse the carbon.  After refilling a cartridge open the flush valve to run water through the GAC to rinse it.  Once water comes out clear close the valve allowing water to move to Stage 2.

STAGE 2 CANISTER has a 1 Micron Sediment Filter which removes sediment like sand, and other particles of 1 micron or larger.  This includes any carbon particles that came loose from the GAC in stage one.   The best gauge of this filters life is a pressure drop.  When we see a 5 PSI drop on the provided pressure gauge, we should change our filter.  Discoloration is also a sign that the filter is loaded and time to replace.  Some silts may clog filter prematurely depending on whats in our city water.

PRESSURE GAUGE tests the pressure entering Stage 3 The RO Membrane.  Optimal pressure is between 45-85 psi.  The gauge will allows us the ability to monitor the pressure
of the system and make sure that the filter is receiving sufficient water pressure to operate efficiently
as well as monitor your pre-filters. It will indicate, via a drop in pressure, when the sediment filter is clogged and need to be replaced.

STAGE 3 RO MEMBRANE  The membrane reduces TDS total dissolved solids, such as salts, heavy metals, or calcium.  This is the most expensive of the replacement filters.  Typically lasting 2-3 times longer than the other filters.  Our goal is to extend membrane life by allowing the GAC and Sediment filter to remove as much as possible before the membrane.  A properly functioning membrane should provide a minimum of 90% reduction in TDS (typically more).  That’s why the MERO units installs  TDS Probe 2 after the membrane and before the DI Resin (Stage 4).  IE:  If city water is entering the system at 100 TDS as indicated by TDS Probe 1.  Then a good membrane will reduce 90%, leaving 10 TDS after the membrane.  This is monitored by looking at TDS probe 2 which reads after the membrane.  As this number drops, run the MERO membrane flush kit for 15 minutes cleaning the membrane.  Membranes can deteriorate due to clogging or scaling so flushing helps extend life.  Membranes also fail due to contact with chlorine or chloramine.  This could be due to high levels in city water, or poor GAC filter upkeep.  Flush the GAC from time to time, and replace as needed.  Along with flushing the membrane periodically.

MEMBRANE FLUSH KIT mentioned above is between Stage 3 and Stage 4.

STAGE 4 DI RESIN  The MERO Deionization (DI) media in a refillable cartridge is the final stage.  This resin will remove the remaining TDS and produce zero TDS water.  This is measured by TDS Probe 3.  A rise in TDS above zero lets us know the resin is becoming exhausted and may need replacing.  MERO uses color changing DI Resin which changes from blue to rust color as the resin gets exhausted; however TDS is a better indicator of when to replace the resin because the color may change to rust before it’s exhausted.  If your membrane is not working properly, it will also lead to an increase in DI exhaustion.   Also if your water has chloramines the DI will remove them; however this will burn up DI resin and be more expensive than replacing carbon.  Deionization resin reduce silica, nitrates and phosphate levels. MERO uses only virgin (not reactivated) nuclear grade color indicating resin of the highest quality.   Would you expect anything different from ME!