Water Filter Media

Media is the working material inside a water treatment tank. The tank and valve are just the container and the timer; the granular bed inside does the actual treatment. Calcite (crushed limestone) dissolves into acidic water to raise pH, Katalox Light catalyzes iron and sulfur out, cation resin exchanges hardness for sodium, activated carbon adsorbs chlorine and odors, and specialty resins target tannins, nitrates, PFAS, or arsenic. When the media wears out you replace the media, not the system.

Calcite is consumed by design, so you top it off rather than replace it. It dissolves into the water exactly as fast as the water is acidic, which is why it can't overcorrect. A typical household adds one 50 lb bag (1/2 cubic foot) every 18 to 24 months; a two-person home stretches to 24 to 36. Check the level by shining a flashlight against the semi-translucent tank wall: when the bed shadow sits in the bottom third, it's time.

Plan on 6 to 8 years in real-world service. Watch Water rates Katalox Light for replacement every 7 to 10 years; our own field experience across hundreds of installs says 6 to 8 is the honest number to budget for. There is no annual maintenance in between, no chemical regeneration, and no salt; the backwash cycle does all the upkeep, which is also why it needs a valve strong enough to lift the bed (a Fleck 2510 class valve, not a 5600).

More than any residential well should ever see. Watch Water rates the media for inlet iron up to 100 mg/L and manganese up to 20 mg/L; we conservatively size systems to 30 ppm iron, 15 ppm manganese, and 10 ppm hydrogen sulfide, and the media also filters sediment down to 3 microns. It wants an inlet pH between 5.8 and 10.5; acidic wells get an acid neutralizer upstream first.

Usually yes: a $295 rebed beats a $2,000 softener. If the valve still cycles and the tank is sound, fresh resin restores like-new softening. A 10x54 (48,000 grain) tank takes 1.5 cubic feet, a 12x52 takes 2. Use 10% crosslink resin on chlorinated city water (it survives up to 1 ppm chlorine, about 50% longer life than standard 8% resin). One honest caveat: if iron killed your resin, fix the iron upstream first or the new bed dies the same way.

Only one blend is designed to be mixed: calcite with FloMag, 90% to 10%, for wells with raw pH between 4.0 and 5.5. FloMag (magnesium oxide) has five times calcite's pH-raising power and must never run alone; without the calcite buffer it can overshoot. Mix it in a clean bin before loading: one bag of calcite to roughly 2 lb of booster per batch.

Everything else stays pure. Watch Water specifically recommends against mixing Katalox Light with other filter materials, and layering carbon over resin or calcite over Katalox gives you two half-beds that each do half a job and backwash at different rates. One tank, one media.

Yes, slightly, and that's the honest trade. Calcite is calcium carbonate: as it dissolves to neutralize acidity, it adds calcium back to the water, which raises hardness in proportion to how acidic the water was. Clack's own datasheet says it plainly: depending on pH and water chemistry, a softener may become necessary after the neutralizing filter.

In practice most homes notice nothing. Wells with meaningful hardness on top of low pH run the acid neutralizer first and a softener after it, which is exactly how our acid neutralizer + softener packages are plumbed.

Katalox Light is dense (about 66 lb per cubic foot), and the backwash cycle is its only maintenance: the valve has to lift and expand the whole bed to rinse out captured iron. Watch Water specs 10 to 12 GPM per square foot of backwash velocity. A Fleck 2510 class valve does that; a 5600 class softener valve cannot lift the bed, the rinse never fully cleans it, and the media eventually fouls no matter how fresh it is.

So: rebedding an existing iron filter with a strong valve, order the bags and go. Pouring Katalox into a tank with a light-duty valve, call us first; the media will be fine but the valve will quietly kill it.

Buy 10% crosslink unless someone gives you a specific reason not to. Crosslink percentage measures how densely the resin bead is built: 10% beads resist chlorine attack far better, withstanding up to 1 ppm of free chlorine with about 50% longer life than standard 8% resin. On chlorinated city water that difference is the whole game. It's the grade we ship in every softener we sell (ResinTech CR10).

The honest caveat is iron, not chlorine: iron fouls any cation resin regardless of crosslink. If your old resin died early on a well with iron, fix the iron upstream (that's what Katalox Light systems are for) before paying for fresh resin.

Household trash, in most municipalities. Spent calcite is crushed limestone, spent resin is inert plastic beads, and spent carbon is charcoal; none are hazardous waste from residential water treatment. Bag it, tie it, bin it. The exception is media from systems treating a confirmed contaminant like arsenic; check local disposal rules for those, or ask us and we'll look it up for your county.

Getting it OUT of the tank is the real job. The water-powered mineral extractor pulls everything including the gravel bed without disconnecting the tank, and turns the worst hour of a rebed into ten minutes.

On a full rebed of a gravel-bedded tank, yes. The gravel layer surrounds the distributor basket at the bottom of the tank, protects it from the weight of the media column, and spreads incoming flow evenly across the bed so the water can't carve a channel down one side. Skipping it on a tank designed for it invites channeling and a cracked basket.

Some modern tanks (Vortech style plates) distribute flow through the plate itself and don't use gravel. Match what came out: if you vacuumed gravel out, put fresh gravel back in; if there was none, your tank doesn't want any. Our filter gravel is washed, dried, and NSF 61 certified, in 50 lb boxes.

Iron, manganese, oil, and heavy chlorine. Watch Water's operating limits for SP3 are specific: iron under 0.3 ppm, manganese under 0.05 ppm, free chlorine under 3 ppm, and no hydrogen sulfide or oil. The NAC coating that turns hardness into harmless micro-crystals gets blinded by iron films, which is why well water usually needs iron treatment upstream of a salt-free conditioner.

Protected properly, the media works maintenance-free with no salt, no drain, and no electricity; we conservatively recommend replacement every 3 to 5 years (the manufacturer rates it 5 to 7). When yours is due, the refill is sold by the liter to match your conditioner size; call and we'll confirm the volume your tank takes.