HydroLogic Hydroid Membrane Element, Hi-Flow RO Replacement (HL 11590)

Hydroid Membrane Element: The RO Stage of the Hydroid

This is the reverse osmosis membrane that does the purifying inside a HydroLogic Hydroid system. The Hydroid holds two of these elements, one in each pressure vessel. HydroLogic describes them as USA-made, commercial-grade hi-flow membranes. The material is a polyamide thin-film composite, the standard chemistry for modern RO elements. Under HydroLogic's test conditions, the element is rated at 3,000 gallons per day, or 125 gallons per hour. That rating is taken at 100 psi of applied pressure. Nominal salt rejection is 95%, with test water at 550 ppm and 77°F. Actual output rises in warmer water and falls in colder water. The Hydroid manual includes a temperature correction table for checking real flow against the rating. A healthy element should come within about 20% of rated production after that correction. The membrane has zero tolerance for free chlorine, which is why the carbon pre-filter matters so much. Oxidation damage from chlorine or chloramines is not covered under warranty.

Running and Replacing a Commercial RO Membrane

Stay inside the operating limits HydroLogic lists for the element. Feed water should stay at or below 85°F, and operating pressure should not pass 150 psi. Continuous operation is rated for a pH range of 2 to 11. Short cleaning cycles of up to 30 minutes can run from pH 1 to 13. The feed water silt density index should be 3 or lower. Keep a weekly log of feed, product and concentrate readings so changes stand out early. When it is time to swap, shut the system down and bleed every gauge to zero first. Coat the brine seal and O-rings with silicone lubricant, never a petroleum product. Follow the flow arrows on the housing and seat the element fully in the bottom end plug. After installation, flush the new membranes for at least half an hour. Discard all purified water made during that flush. Keep the elements wet once they have been run, and store them in preservative during a long shutdown.

Key Features

• Polyamide thin-film composite: Commercial-grade, hi-flow element made in the USA.
• 3,000 GPD rating: 125 gph at 100 psi under HydroLogic test conditions.
• 95% nominal salt rejection: Tested at 550 ppm feed water and 77°F.
• Wide pH tolerance: pH 2 to 11 in operation, 1 to 13 during short cleanings.
• OEM part HL 11590: The membrane specified in the Hydroid manual, two per system.

Technical Specifications