Hydro Logic Stealth-RO300 Reverse Osmosis Filter, 300 GPD

Hydro Logic Stealth-RO300 Reverse Osmosis Filter, 300 GPD

Hydro Logic Brand Product
$219.95 - $229.95

Availability: In stock

Lead time: Please select an option below


Produces up to 300 gallons per day of ultra-pure, low PPM water. Removes 98%+ of chlorine & contaminants. Wastes approximately 50% less than other RO systems. Everything included in the box for quick hook-up. Customized for gardening & hydroponics.

Choose from a 1:1 or 2:1 waste to product water ratio (both included with unit). Also an ultra-efficient 1:1 ratio available as optional accessory.

  • Stabilize - PH levels and avoid mineral build up.
  • Maximize - nutrient uptake and minimize lock out for your priced plants
  • Essential - for health of beneficial micro-organisms

This System Includes:

  • Membrane Power Flush Kit
  • Stage 1: Pleated, Cleanable Sediment Pre-Filter - reduces dirt, sediment, silt, rust, etc
  • Stage 2: Green Coconut Carbon Block Pre-Filter – reduces chlorine and other toxins
  • Stage 3 & 4 – (2) 150 GPD Reverse Osmosis Membranes - reduces total dissolved solids
  • Inlet Pressure Gauge - shows dynamic line pressure and optimal operating zones
  • 5 feet white 3/8″ inlet tubing, 8 feet black 1/4″ waste water tubing, 8 feet blue 1/4″ purified water tubing
  • Garden Hose Connector with 3/8″ Quick Connect - for quick and easy hookup to source water
  • Double-Ended Filter Housing Wrench - large end for pre-filter housing sumps, small end for membrane housing cap
  • Optional Eco-Waste Reducer - gives 2:1 waste to product water ratio

Optional KDF85 Carbon Filter Upgrade

For chlorine and chloramines reduction for city water. Also for well water for iron, hydrogen sulfide, and heavy metals reduction. Will last TWO TIMES AS LONG - 2,000 Gallons as the standard green carbon filter. Prolongs the life of the membranes. Reduces chloramines, chlorine, iron, sulfur and heavy metals. Bacteriostatic qualities do not allow microbes to breed in filter.

Check out all of the optional add-ons, upgrades and filters for the Hydro Logic Stealth RO300:

  • TDS Meter
  • Eco-Waste Reducer
  • UV Sterilizer Kit
  • De Ionization Kit
  • And More!
Product Q&A

Hydro Logic Stealth-RO300 Reverse Osmosis Filter, 300 GPD Questions & Answers

I have well water, what challenges can I expect?
Here are the most common challenges when filtering well water:

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

How does reverse osmosis affect pH?
RO product water can have a lower pH than the feed water. It depends on the level of dissolved CO2 in the feed water.  A lowering of pH can ocurr because the existing CO2 in the water, being a gas, passes through the membrane but the alkaline constituents, primarily HCO3 (bicarbonate), are removed as part of the reject water. In the feed water the HCO3 neutralizes the acid-causing CO2. In the product water, with HCO3, greatly reduced, the CO2 is free to combine with the H2O to form carbonic acid: CO2 + H2O > H2CO.

Another reason to question the pH reading is that for any water sample which is very low in TDS it is very hard to obtain an accurate pH value. The worst case of this accuracy problem occurs with de-ionized water but some low TDS RO water will react the same. The sample is so low in minerals that there is no buffer. The slightest absorption or loss of CO2 shifts the pH substantially. The water’s tendency to pick up additional CO2 from the ambient air, even if the test is done on site, can produce a very low false pH.

In reality, measuring the pH of RO water is difficult and not accurate due to lack of any pH buffering the RO water. If the feed water has a lot of dissolved CO2 then pH can drop a few points. But, in the case of a drinking water RO system, a post re-mineralization filter will help neutralize the final product water's pH level. In the case of RO water for horticultural purposes, once you mix a calcium/magnesium supplement into the RO water and then add your nutrients and additives, the final pH can be adjusted and your feed formula should be pH stable.

Why do pH levels come out higher than the source water when running water through a carbon or Carbon/KDF filter?
This is common, there is generally a significant pH spike from the GAC (granular activated carbon) that is mitigated relatively quickly after start up. For some systems, it can take days or even weeks to run enough rinse water to get the pH back to normal. Since it is temporary, it is generally not a significant issue.

How do I properly store a Reverse Osmosis System that won't be used for more than 3 weeks
Reverse osmosis membranes like water to run through them often in order to perform properly. Running water for once a day for a short period of time is ideal, but even once a week is sufficient. If you are not going to use your reverse osmosis system for 3-4 weeks or longer, there are storage procedures you should follow to maintain optimum system performance. Take the membrane(s) out of the system and place in a plastic bag and put them in the refrigerator. A white plastic kitchen bag with a knot tied at the top works well. Take the carbon filter(and in some systems such as the Stealth 100/200 the sediment filter as well) out of the housing and let it(them) dry out. Leave the housings and the caps on the system unscrewed to let them dry out. The purpose of this is to not trap wet filters and moisture in the system so that bacteria will not grow. As an extra measure of precaution, sterilizing using a light bleach or hydrogen peroxide solution to clean the housings, tubing and fittings is a good idea before using the system again.

How do I know if I have iron in my water?
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.


Customer Reviews 11 item(s)

Grow Saver!!
Great system. Very compact and portable if needed. Excellent results!
Wonderful product easy to use
wont make 300 gpd
have to meet certain requirements that are in the fine print like 80 psi
Making Good Water
I am very satisfied with my R0300 that I installed in my Motor Home. Also helpful support/ Thank you.
House ppm was 760-900 and this dropped my ppm to 0! Absolutely stoked!
Too slow
With 45 psi only creates about 6 gallons per hour clean water. Less than half the advertised flow rate. You have to buy it to read all the qualifiers about water temperature and line pressure needing to be ideal to get the advertised flow rate. Totally overpriced!
Extremely happy with this product!
My product was shipped very fast, and this was the best price I could find. I have already recommend this product to several of my friends. It's very easy to install and works very well!
Clean water
Great performance and output for my 50 gallon tank. The difference in ppm dirty to clean is notable.
0 ppm easy to use
if you don't want to die from cancer buy one. the tap water is full of fecal matter Rust fluoride chlorine etc buy the drinking water unit with this product. Family is all we have shouldn't we give them clean healthy water? One LOVE
Perfect for my use
I've had this RO device working in my garden for a month now. It receives water from our well at 140 ppm, and delivers pure RO water at 2 ppm. The rate of product water delivered is very good, able to fill containers rapidly. My inlet pressure is less than 40 psi, so I have to use a boost pump to get the inlet pressure up near 80 psi. At that increased pressure, the RO300 works perfectly.
Great RO unit, great price
This unit has been working perfectly for our greenhouse deep water culture system. Highly recommended.
Tech Specs

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