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micRO-75™ Reverse Osmosis System

  • An economical, entry-level, micro-sized, portable reverse osmosis system. Includes KDF85/carbon filter and 75 GPD membrane, perfect for hydroponic gardens requiring up to 75 gallons per day. Check out these exclusive features, nothing else compares at this price:

    • Produces up to 75 GPD (gallons per day)/3 GPH (gallons per hour) of ultra-pure, low PPM water (Flow rates of RO systems are based on source water @ 65 psi/77°/500 ppm)
    • Removes up to 98%+ of all contaminants
    • KDF85 media added into carbon pre-filter: For heavy metal reduction
    • Replaceable carbon filter: More earth-friendly and affordable to change only the filter not the entire housing
    • Metal bracket: Filter is stable on a flat surface or can be wall-mounted
    • Integrated pressure gauge with safe zones: Easy to monitor
    • Automatic Shut-off Valve (ASOV): So drain line shuts down when product line is shut down
    • External flow restrictor: For 2:1 drain to product water ratios
    • High rejection RO membrane built to American standards
    • Meets or exceeds NSF certification standards
    • Dimensions (H x W x D): 6" x 15" x 5"
    • Weight: 6 lbs

    Filters & Replacement Schedules

    Carbon Filter
    • Replace after 1,000 gal (Schedules for Reverse Osmosis carbon filters based on product water)
    RO Membrane
    • Replace between 6–18 months
  • micRO-75 Downloads


    HydroLogic Blog Articles

Part Number: HGC741627
UPC: 812111011970

When do I change the filter?

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The micRO-75™ Reverse Osmosis System comes with the following parts


        Q: The system is brand new, why is the flow rate of purified water so slow?

        A: The system’s GPD capacity is achieved when you have the following conditions for your source water: 77°F, 500 ppm, 60 psi. If your source water is colder than this, or your inlet pressure is lower, or your PPMs are significantly higher, then you will experience less than the rated GPD flow rates. HydroLogic provides solutions to these less-than-desirable source water conditions. For instance, we have a pressure booster pump for low psi, pre-filtration for high PPMs, and cold water specific membranes. Call us at (888) 426-5644 for information.

        Q: Why has the flow rate of purified water slowed down over time?

        A: This can be due to multiple factors, such as clogged sediment or carbon pre-filter, clogged or fouled membrane, or changes to source water conditions. The quality of your water, frequency of use, and timeliness of pre-filter changes will determine how long your system performs at peak capacity.

        Q: Why have the PPMs of the purified water increased over time?

        A: This is typically due to deterioration of the membrane as a result of exposure to chlorine. The purpose of the carbon filter is to remove chlorine from the water. If it isn’t changed on schedule, chlorine will pass through to the membrane and degrade it, causing more water to flow out of the purified line and an increase in PPMs.

        Q: Why is the waste line running faster than the purified water line?

        A:If you’re using the 2:1 flow restrictor, that means the system will produce 2 parts waste water to one part purified water. If you’re using the 1:1, you should have equal parts waste to purified water.

        Q: Why does the waste line continue to run when the purified water line is closed off?

        A: Over time, the automatic shut-off valve (ASOV) can accumulate scale and become clogged, causing it to malfunction. If you experience your waste line continuing to run after the purified water line is closed, please give us a call at (888) 426-5644.

        Q: Why is the system leaking?

        A: This can be due to various reasons, including Teflon tape at threaded fittings, tubing not being pushed in all the way to the quick-connect (QC) fittings, or improperly seated O-rings in pre-filter and membrane housings. It is also important to make sure the ends of the tubing have a clean cut before inserting them into the QC fittings (see page 7 of the micRO-75™ User Manual) Please call us at (888) 426-5644 if you’re experiencing any leaks.

        Q: Why did the clear pre-filter housing crack?

        A: This can be due to freezing conditions, excessive pressure spikes, or long-term exposure to high intensity lighting.

        Q: Why is the pH of the purified water higher/lower than the source water

        A: The pH of the purified water depends entirely on source water chemistry. Customers can experience either slightly lower or higher pH due to their source water. This is completely normal for reverse osmosis technology. Since RO water is almost pure H2O and has no ability to buffer pH, the actual pH reading will not be accurate until you add minerals back.

        Q: I have well water, what challenges can I expect?

        A: Here are the most common challenges when filtering well water:

        • It is typically colder which will decrease your flow rates because cold water flows slower through a reverse osmosis membrane
        • Often has higher PPM/TDS levels (hardness) which can decrease the life of a membrane
        • Can contain high levels of sediment which can easly clog a carbon or sediment prefilter
        • Can have high levels of iron, manganese and hydrogen sulfide (rotten egg smell)
        • It occassionaly contains iron bacteria which is difficult to remove
        • It generally has low water pressure

        Q: How do I treat water containing iron?

        A: There are different methods of treating iron depending on how much iron is present in the source water. The easiest way to know how much iron you have is to get your water tested from NTL.

        • For a city water analysis use product code: 9001
        • For a well water analysis use product code: 9003
        Once you have your water analysis, please contact us at (888) 426-5644 with your water report and we can assist you with choosing an appropriate prefiltration method.

        Q: How do I know if I have iron in my water?

        A: If your carbon or sediment filter appears to be red, maroon, orange or brown in color you have iron in your water. You may also notice that your sinks and or toilets also have this discoloration. See an example image below of a system that was used to filter water with excessive iron levels.

        filter water with excessive iron levels;