RO Membrane Replacement Filter for Tankless RO RCT600Mfr #: MC600 Dedicated RO membrane for iSpring countertop RO water filter system RCT600. Experience clean and fresh water every time you turn on your drinking water faucet. This core of RCT600 is rated at 600 gallons per day. With up to 1. 5: 1 pure water to wastewater ratio, RCT600 is much more efficient than a traditional RO membrane. MC600 removes up to 99% of over 1, 000 contaminants, including lead (up to 98%), chlorine, fluoride, arsenic,