PoolRx

PoolRx is registered with the EPA as a mineral algaecide, Reg. No. 79817-3, and its active ingredient is chelated copper sulfate pentahydrate at 52.8 percent, copper as metallic not less than 25 percent. The same registration is sold under the alternate brand name Leslie's MineralRx.

The label is explicit that it works alongside chlorine rather than instead of it, and it names the level: a constant 0.5 to 1.0 ppm for residential pools, 1.0 to 5.0 for commercial. It also sets the water it needs — pH 7.2 to 7.8, alkalinity 80 to 120, cyanuric acid 10 to 80, TDS under 3,000 ppm. A pool that cannot hold those numbers is not a pool PoolRx will fix.

One instruction is easy to miss and undoes the install: do not clean or backwash the filter for at least two weeks after fitting a unit, so the granular mineral can dissolve through it. Our review of PoolRx covers how that plays out in practice.

The minerals work for up to six months, but the label's replacement schedule is annual: replace the pool unit in the skimmer basket every 12 months, and start each season with a new one. A commercial unit is cleaned every 12 months and replaced every three years.

In between, a booster replaces the granular lost to backwashing, splash-out and killing algae, and the label puts that at four to six months, as needed — the trigger being algae returning or the water looking dull rather than a date. The booster only works with a pool unit already in place.

The part numbers are on the label rather than the box: the blue residential unit is #101001, the commercial unit #101080, and boosters are 102001 and 102066. One consequence of any copper product is worth planning for before you fill a tanker: the label tells you to contact your local sanitary sewer and storm drain authorities before draining a treated pool, and not to discharge it anywhere that reaches a storm drain or a natural water body without permission.