By salt-regenerated anion exchange. The tank holds 1.5 cubic feet of ResinTech SBACR-HP, an acrylic gel strong base anion resin in chloride form, designed specifically for organics and color removal from potable water. Tannins carry a slight negative charge, so as water flows through the bed the resin swaps harmless chloride ions for the tannin molecules and holds them by both ion exchange and adsorption. When the metered valve regenerates with a sodium chloride brine (ordinary water softener salt), the organics flush to the drain and the resin restores to chloride form. Same mechanic as a water softener, with a resin engineered for organics instead of hardness.

Tannins are an aesthetic problem, not a health hazard. They are natural organic compounds from decaying vegetation, common in shallow wells and in marshy, low-lying, or coastal areas. The EPA covers them under its secondary (non-enforceable) standards: color becomes objectionable to most people above 15 color units. That said, yellow or tea-colored water still deserves a lab test, because discoloration can also signal iron, manganese, or surface water getting into the well, and those have different fixes.

Two checks. The quick one: fill a clear glass and let it sit overnight. Color that settles to the bottom is likely ferric iron or sediment; water that stays uniformly tinted is dissolved organics, meaning tannins. The reliable one: a certified lab test, where the parameter is reported as Tannin-Lignin. The distinction matters because iron needs an iron filter, not anion resin, and if your test shows meaningful iron alongside low tannins, we'll tell you to treat the iron first.

The 6 GPM unit (1.5 cu ft, 10x54 tank) fits homes with 1-2 bathrooms. The 10 GPM unit (2.5 cu ft, 13x54 tank) fits homes with 3+ bathrooms or heavier tannin loads, since more resin means more contact time. This 6 GPM unit is the right size for the typical 1-2 bath well home. Tannin removal is contact-time limited, so unlike a softener you should not undersize and lean on peak valve flow. If your home has unusually high flow demands, two units can be plumbed in parallel. When in doubt, call or text us with your bathroom count and water test and we'll size it in two minutes.

No. Softener resin is a cation resin: it captures positively charged calcium and magnesium. Tannins are negatively charged organics and pass straight through. The two systems are partners, not substitutes: hardness fouls anion resin, so the industry-standard order is softener first, tannin system after it. The softener extends the tannin resin's life and improves its removal. Do not mix cation and anion resin in one tank - mixed beds regenerate poorly and underperform at both jobs.

At a single tap, yes - RO rejects dissolved organics well. But tannins are a whole-house problem: they stain laundry, fixtures, and tubs at every tap, not just the kitchen sink. Whole-house RO is a $5,000-$10,000 proposition, and organics are exactly what fouls RO membranes and carbon filters early. That is why salt-regenerated anion exchange is the standard residential fix: it treats every tap, regenerates itself with softener salt, and protects any downstream RO you add for drinking water.

Anion exchange removes some alkaline ions along with the tannins, so treated water typically drops about a point of pH until the resin's capacity for those ions saturates. We see it in the field regularly: a well at 7 lands around 6 after the tannin unit. The fix is an acid neutralizer installed after the tannin system to bring pH back to neutral, protecting your copper pipes and fixtures. If your well already runs low pH, plan the neutralizer into the build from day one - tell us your pH number and we'll spec it.

Tannin systems regenerate more often than a softener on purpose. Organic molecules that sit on the bed too long migrate into the resin matrix and become very hard to strip, so the standard guidance is to regenerate every two to three days rather than stretching capacity. The metered valve handles the schedule automatically; your job is keeping water softener salt in the brine tank. Expect somewhat higher salt use than a same-size softener - that's the cost of keeping the bed healthy for years instead of replacing fouled resin.

Years, if it regenerates frequently. The acrylic structure of SBACR-HP is the key: unlike traditional styrene-based anion resins, it releases captured organics during the brine cycle instead of holding them, which is what normally kills tannin beds. The classic warning sign of a fouling bed is a fishy or musty odor in the treated water; a cleaning cycle with salt and baking soda usually restores it. When capacity finally declines after years of service, you rebed the tank with replacement tannin resin (we sell it by the cubic foot) rather than replacing the system.

Yes, always. Yellow water has multiple causes and they need different equipment. Our $99 tannins water test kit is a certified lab analysis that reports Tannin-Lignin plus the iron, hardness, and pH numbers we need to size the system and plan the treatment order. Real example from our support line: a customer's lab showed 1 ppm tannin alongside 1.5 ppm iron, and the right answer was an iron filter, not a tannin system. Send us your results and we'll personally confirm the right system before you spend anything.