:rimshot:~ FREE TDS meters on ALL orders over $40! ~ (enter code: "FREETDS" in your cart) Don't forget to credit Northeast Florida Marine Aquarium by using your club's unique 10% off code: (enter code: "41216" in your cart). Enter your discount code(s), click the orange "apply coupon" button in the discount codes section of your shopping cart at www.theH2Oguru.com. Happy Reefing, your friends at Air Water & Ice. We're always here for you. Email: [email protected] OR call 772-461-0256 for over 30 years experience in helping saltwater tank owners get the BEST results for LESS than ANY of my competition. Don't waste your fish $$$ on expensive prefilters that DO NOT REMOVE ANY TDS...you NEED our NEW series of Filmtec membranes (they are not all the same)...ASK us about our 99% rejection, mild chlorine tolerant, high rejection filmtec membranes and because these specs are tested at 50 PSI you will find my membranes get over 20% more GPD than any other brand or series of membrane. ADD this membrane in front of my nuclear grade DI resin...and be amazed how much longer your DI resin lasts!