Ground Shipping Only: This product ships via UPS Ground only.

BioGuard Pool Magnet Plus | Metal Stain Preventer

SKU: 23454BIO
$25.99

Check Discount Eligibility
Returns On Hazardous Materials
Low stock

Pickup available at Leisure Time Inc. - Idaho Falls

Usually ready in 24 hours

View store information


Description

BioGuard Pool Magnet Plus is a concentrated sequestrant that locks iron, copper, and manganese in solution so they can't stain your pool. It also eliminates discolored water caused by dissolved metals — the brown, green, or tea-colored tint that shows up when metal-laden fill water meets chlorine.

Metal staining is one of the more discouraging problems in pool ownership because it looks like permanent surface damage. What's actually happened is that dissolved metal — from well water, a corroding heater or fitting, or the municipal supply — came out of solution and deposited on the finish. The usual trigger is chlorination: raising the chlorine level oxidizes dissolved metals and drops them onto whatever they land on. That's why stains so reliably appear right after opening or right after a shock treatment, seemingly from nowhere.

A sequestrant intervenes ahead of that reaction. Its molecules bind the metal and hold it chemically unavailable, so chlorine can't precipitate it. The metal stays dissolved and harmless, circulating with the water rather than depositing on it.

The formula has been recently reformulated and is more concentrated and effective than the version it replaced. It stays effective for three to four weeks, which is why monthly application covers the interval — pool professionals recommend monthly use in any pool filled with iron-containing water.

It also removes fresh metal stains, at a heavier dose scaled to how bad the staining is. And BioGuard specifically recommends pairing it with a filter aid: the sequestrant holds the metal in suspension, and the filter aid gives your filter the ability to actually capture and remove it. Sequestering alone manages the metal; sequestering plus filtration gets it out of the pool.

Pro Tip: Add this before you chlorinate a fresh fill, not after you see a stain. Chlorine is a powerful oxidizer, and raising the chlorine level is precisely what knocks dissolved iron and copper out of solution and onto your pool surface. The metal was in the water the whole time — invisible and harmless — until something precipitated it. If you're filling from a well, or topping off substantially, dose the sequestrant first and let it circulate before adding sanitizer. Five minutes of sequence discipline prevents a stain that costs a multi-step protocol and several products to remove.

Brand

BioGuard®

What's in the Box
  • 1 x BioGuard Pool Magnet Plus, 1 quart (32 fl oz) bottle
  • Full manufacturer label with dosing rates for prevention, maintenance, and stain removal

Note on quantity: the stain prevention dose uses the entire quart per 10,000 gallons. A 20,000-gallon pool needs two bottles for that treatment. Fresh stain removal runs 32 to 96 fl oz depending on severity — one to three bottles per 10,000 gallons. Calculate your total before ordering.

Key Features

Prevents Stains Caused by Metals

Binds iron, copper, and manganese so a chlorine addition or pH shift can't drop them onto your pool surface as brown, green, or black staining.

Eliminates Discolored Water from Metals

Clears the brown, green, or tea-colored tint that dissolved metals produce — a problem no clarifier or sanitizer addresses.

Removes Fresh Metal Stains

At a heavier dose, lifts recent staining back into solution, with the amount scaled to how severe the staining is.

Concentrated, Reformulated Formula

More concentrated and more effective than the previous version, delivering greater protection per ounce.

Stays Effective 3–4 Weeks

Long enough that a monthly application genuinely covers the month rather than fading after a week.

Easy to Apply

Pour directly into the pool with the pump running. No dilution, no pre-mixing, no special equipment.

Recommended Monthly for Iron-Containing Fill Water

Pool professionals recommend monthly use in any pool filled with iron-bearing water — which covers most well-water pools.

Works With a Filter Aid to Remove Metals

Pairing with a filter aid gives your filter the ability to physically capture the sequestered metal, so it leaves the pool instead of circulating indefinitely.

How It Works

Pool Magnet Plus is a sequestrant, sometimes called a chelating agent. Its molecules bind to dissolved metal ions — iron, copper, manganese — and hold onto them, keeping them locked in solution and chemically unavailable to react.

The problem it prevents runs like this. Metals enter pool water dissolved and invisible: from well water, municipal supply, corroding heater components or metal fittings, or a copper-based algaecide. While they stay dissolved, nothing looks wrong. The trouble starts when the metal is oxidized. Chlorine is a powerful oxidizer, so raising free chlorine converts dissolved iron into an insoluble oxide that falls out of solution and bonds to whatever surface it settles on.

That's why stains so frequently appear immediately after opening a pool or after a shock treatment — the metal was there the whole time, waiting for something to precipitate it. It's also why discolored water shows up the same way: metal oxidizing in the water column tints it before it ever reaches a surface.

A sequestrant intervenes ahead of that reaction. By binding the metal ion, it prevents the oxidation that would drop it out of solution. Chlorine can't reach it, so nothing precipitates and nothing stains.

The same mechanism explains fresh stain removal. A stain that hasn't fully bonded to the surface can still be pulled back into solution by a heavy sequestrant dose. Once a stain has aged and set into the finish, the bond is too strong — that requires a dedicated stain remover with reducing chemistry and a full multi-step protocol.

Here's the important limitation, and it's the reason for the filter aid recommendation. A sequestrant manages metal; it doesn't remove it. The metal is still in your water, held in a form that can't stain. Sequestrant molecules are gradually consumed and lost through filtration, splash-out, and dilution, which is why protection fades after three to four weeks and why monthly dosing is required. To actually get the metal out of the pool, the filter has to capture it — and sequestered metal exists as extremely fine particles that a filter can't normally catch. A filter aid gives the media the capability to trap them.

Pro Tip: Pair this with a filter aid if you want the metal gone rather than just managed — BioGuard recommends the combination specifically. On its own, a sequestrant holds metal in suspension indefinitely, which means you're re-dosing every month forever to keep it from staining. Adding a filter aid lets your filter physically capture the sequestered metal so it leaves the pool for good, and each subsequent month there's less to manage. On a well-water pool with a heavy iron load, that combination is the difference between a permanent monthly expense and a problem that gradually shrinks.

Directions for Use

Dosage Reference

Read the units carefully — the maintenance dose is stated per 1,000 gallons, not per 10,000.

  • Stain prevention: 32 fl oz per 10,000 gallons
  • Maintenance dose: 3 fl oz per 1,000 gallons — which works out to 30 fl oz per 10,000 gallons
  • Removal of fresh stains: 32 to 96 fl oz per 10,000 gallons, depending on the severity of the stain

Always confirm the rates on your current product label before dosing, and calculate against your pool's actual gallon capacity.

Before You Start

  1. Confirm the pump and filter are operating and circulating normally.
  2. Test for metals and confirm which metal you're dealing with, if you can — iron reads rust-brown, copper blue-green, manganese black or purple-brown.
  3. Confirm your pool's actual gallon capacity.
  4. Decide which of the three doses applies before you measure.

Stain Prevention

  1. Apply 32 fl oz per 10,000 gallons of pool water.
  2. Add directly to the pool with the pump running, distributing around the perimeter.
  3. Allow the water to circulate to distribute the product.
  4. On a fresh fill, apply before raising the chlorine level.

Monthly Maintenance

  1. Apply 3 fl oz per 1,000 gallons of pool water — 30 fl oz for a 10,000-gallon pool.
  2. Add directly to the pool with the pump running.
  3. Repeat monthly. The product stays effective three to four weeks, so monthly application maintains continuous protection.
  4. Pool professionals recommend monthly use in any pool that holds iron-containing fill water.

Removal of Fresh Stains

  1. Apply 32 to 96 fl oz per 10,000 gallons, depending on the severity of the staining.
  2. Add directly to the pool with the pump running, concentrating over the stained areas.
  3. Brush the stained areas to help the treatment reach the deposit.
  4. Circulate continuously and allow time for the metal to return to solution.
  5. Follow with a filter aid so the filter can capture and remove the released metal.
  6. Repeat if staining persists. Aged staining that has set into the surface requires a dedicated stain remover instead.

Preventing Recurrence

  • Test for metals at opening and after any significant refill
  • Maintain the monthly dose if your fill water carries iron
  • Keep pH at 7.4–7.6 — acidic water accelerates corrosion of metal equipment and adds metal to the pool
  • Address the source where you can: a corroding heater or fitting keeps feeding metal in no matter how much sequestrant you add
  • Pair with a filter aid to physically remove metal rather than managing it indefinitely

Storage and Handling

  • Store in a cool, dry, well-ventilated area, out of direct sunlight and protected from freezing
  • Keep the container tightly closed and clearly labeled
  • Store separately from sanitizers, acids, and oxidizers
  • Keep out of reach of children and pets
  • Read and follow all label precautions, first aid, and disposal directions before use

Pro Tip: A sequestrant manages the symptom — find out where the metal is coming from. Well water is the obvious culprit, but a corroding heater core, corroding metal fittings, or a copper-based algaecide will all feed metal into the pool continuously, and you'll be dosing forever without fixing anything. Chronically low pH is the common hidden cause: acidic water actively dissolves copper out of heat exchangers and plumbing, which means the stain you keep treating is literally your heater dissolving into the pool. Keep pH at 7.4–7.6, get a full water test that includes metals, and if the number climbs between treatments, something in the equipment pad is the source.

Specifications
  • Brand: BioGuard
  • Product Type: Concentrated metal sequestrant and stain preventer
  • Form: Liquid concentrate
  • Volume: 1 quart (32 fl oz)
  • Manufacturer Part Number: 23454BIO
  • Controls: Iron, copper, and manganese
  • Also Eliminates: Discolored water caused by metals
  • Stain Prevention Dose: 32 fl oz per 10,000 gallons
  • Maintenance Dose: 3 fl oz per 1,000 gallons — 30 fl oz per 10,000 gallons
  • Fresh Stain Removal Dose: 32–96 fl oz per 10,000 gallons, by severity
  • Working Duration: 3–4 weeks after application
  • Recommended Frequency: Monthly in pools with iron-containing fill water
  • Formulation: Recently reformulated — more concentrated and effective than the previous version
  • Application Method: Add directly to the pool with the pump running
  • Companion Product: Use with a filter aid to physically remove metals from the water
  • Chlorine Content: None
  • Suitable Surfaces: Plaster, gunite, vinyl liner, fiberglass, painted
  • Sanitizer Compatibility: Chlorine, bromine, and salt generator pools
  • Not A Substitute For: Sanitizer, clarifier, or a dedicated stain remover for aged stains
  • Shipping Classification: DOT-regulated — ground shipping only
Compatibility

Pool Types and Surfaces

  • In-ground and above-ground pools
  • Plaster and gunite
  • Vinyl liner
  • Fiberglass
  • Painted surfaces
  • Sand, cartridge, and DE filtration

Metals It Controls

  • Iron — the most common, producing rust-brown or reddish staining and tea-colored water
  • Copper — blue-green or teal staining, often from corroding heat exchangers or copper algaecides
  • Manganese — black or purple-brown staining, typically from well water

Sanitizer Programs

  • Chlorine pools — the intended application
  • Bromine pools — compatible
  • Salt chlorine generator pools — compatible; salt pools produce chlorine continuously, so sequestrant protection matters just as much
  • Mineral system pools — verify with your dealer, since mineral systems intentionally maintain metals in the water

When You Need It

  • Well water fill — the classic case, and where monthly use is recommended
  • Any pool filled with iron-containing water, including some municipal supplies
  • At every fill or significant top-off, before chlorinating
  • Pools with a history of metal staining or discolored water
  • After using a copper-based algaecide, which introduces copper deliberately
  • As a required step in a metal stain removal protocol

Role in the Metal Stain Removal Protocol

Pool Magnet Plus is a specified step in BioGuard's stain removal sequence. After a stain remover releases deposited metal back into the water, the sequestrant binds it so chlorine can't precipitate it again — then a filter aid and filter cleaner get it out of the water and the media. Skipping the sequestrant is why so many stain-removal attempts fail: the stain lifts, normal chlorination resumes, and the metal settles right back down within days.

Fresh Stains Versus Aged Stains

  • Fresh staining — a heavy dose of this product, scaled to severity, can lift metal that hasn't fully bonded to the surface.
  • Aged staining — a sequestrant can't reach metal that has set into the finish. That requires a dedicated stain remover and a full protocol, or in severe cases draining and acid washing on white plaster pools only.

What It Does Not Do

  • Not a sanitizer. Provides no disinfection.
  • Not a clarifier. It clears metal discoloration, not suspended particles.
  • Does not remove metal from the water on its own. It holds metal in a non-staining form; a filter aid is needed to actually capture and remove it.
  • Not a fix for aged staining. Set-in stains need a dedicated remover.

Important Handling Cautions

  • Never mix with other chemicals. Add products separately with circulation between additions.
  • Add before chlorinating a fresh fill, not after.
  • Maintain the monthly dose in problem water — protection fades after three to four weeks.
  • Watch the dosing units. The maintenance rate is stated per 1,000 gallons; other rates are per 10,000 gallons.

Most products purchased from our online shop within the last 30 days are eligible for return. Please review our return policy to see the list of items that cannot be returned.

Some major items that are non-returnable:

  • Gift cards
  • Electronics
  • Pumps / Motors
  • Hot Tubs
  • Closeouts
  • Fireplaces
  • Electric Fireplaces
  • Massage Chairs
  • See return policy below for full list of non-returnables.

BioGuard® Brand FAQs

What is the BioGuard 3-Step Care System?

It's the brand's core program for traditional chlorine pools, and it reduces routine care to three jobs.Step 1, sanitize— SilkGuard Complete® tabs or sticks maintain a continuous chlorine residual that kills bacteria and controls algae between applications.Step 2, shock— Smart Shock® is applied weekly to oxidize the organic waste bathers leave behind, break apart chloramines, and restore clarity.Step 3, prevent— Algae Complete® stops algae before it establishes rather than fighting it after it blooms. The system works in pools of any size and surface type that circulate 10 to 24 hours per day.

What's the difference between BioGuard and SpaGuard?

They're sister brands from the same water-care company.BioGuard is the swimming pool line. SpaGuard is the spa and hot tub line.The split isn't marketing — pool dosing is calculated for tens of thousands of gallons at ambient temperature, while spa dosing is calculated for a few hundred gallons at 100°F. Pool packaging makes accurate spa measurement nearly impossible, and a pool-sized dose in a hot tub is a serious overdose. Match the product line to the vessel.

Which BioGuard program is right for my pool?

Equipment usually decides it. Pools running a standard chlorinator, feeder, or skimmer application belong on the3-Step Care System. Pools with a salt chlorine generator should be on thesalt pool programs— Mineral Springs® or SaltScapes® — which are formulated around the specific scale, balance, and cell-care demands of a generator. Owners who want no chlorine or bromine in the water at all use BioGuard'snon-chlorine biguanide program, which is a fully separate chemistry with its own sanitizer, oxidizer, and algaecide.

Can I mix BioGuard products with chemicals from other brands?

Basic balancers are chemically generic and generally interchangeable — alkalinity increaser is sodium bicarbonate no matter whose label is on the bucket. The real risk sits withsanitizer programs and specialty additives. Never introduce chlorine or bromine into a biguanide pool; the two chemistries destroy each other and produce cloudy water, gummy filter fouling, and a collapsed sanitizer residual. Also avoid stacking algaecides and clarifiers from different brands, since overlapping actives can cause foaming or staining. And regardless of brand, never combine two products in the same bucket, scoop, or feeder — always add them separately with circulation running between.

What is SilkGuard Technology?

SilkGuard® is a conditioning technology built into BioGuard's chlorinating tabs and sticks. It softens the feel of the water against skin and helps protect pool surfaces and equipment from scale formation, so the sanitizer is doing two jobs at once. SilkGuard Complete® products also carrySunShield® Technology, which shields free chlorine from ultraviolet breakdown. UV loss is the largest single drain on chlorine in an outdoor pool during summer, so protecting the residual directly reduces how much sanitizer you consume over a season.

Do BioGuard products work with salt chlorine generators?

Yes. A salt pool is still a chlorine pool — the generator simply produces the chlorine on site instead of you adding it from a bucket. Salt pools still need balancing, weekly oxidation, algae prevention, and scale protection, and they have one extra demand a standard pool doesn't: the generator cell itself accumulates scale and needs periodic cleaning. BioGuard's salt-specific programs are built around exactly those requirements.Do not skip testing on a salt pool— the automation controls chlorine production, not water balance.

About BioGuard®

BioGuard is a professional swimming pool care line built on a simple premise: pool chemicals work better as a program than as a shelf of unrelated purchases. Most water problems homeowners fight through the summer aren't caused by a bad product. They're caused by good products working against each other, applied out of sequence, in water whose balance was never corrected in the first place. BioGuard's entire approach is organized around fixing that — matched products, a defined order of operations, and a diagnostic process behind the recommendation.

The brand sits under the KIK Consumer Products umbrella alongside its spa counterpart, SpaGuard, and it covers the full range of pool water care: sanitizers, shocks, algaecides, balancers, water enhancers, surface cleaners and problem solvers, salt pool products, and off-season closing chemistry.

Three Programs, One Philosophy

  • Traditional Chlorine — the 3-Step Care System — Sanitize, shock, prevent. SilkGuard Complete® tabs and sticks handle daily sanitation, Smart Shock® handles weekly oxidation and clarity, and Algae Complete® handles algae prevention. Suitable for pools of any size and surface type running 10 to 24 hours of circulation per day.
  • Salt Pools — Purpose-built chemistry for pools with a chlorine generator, including the Mineral Springs® and SaltScapes® programs. Salt pools still generate chlorine, and they still need balancing, scale protection, and cell care — these products are formulated for that specific equipment set.
  • Non-Chlorine Pools — A complete biguanide-based program for owners who want no chlorine and no bromine in the water at all, with its own dedicated sanitizer, oxidizer, and algaecide.

Formulation Technologies

Two proprietary technologies show up across the chlorine line and explain a lot of the brand's reputation. SilkGuard® Technology conditions the water so it feels noticeably softer against skin while also helping protect pool surfaces and equipment from scale. SunShield® Technology protects free chlorine from ultraviolet breakdown, which is the single largest source of chlorine loss in an outdoor pool during summer — sanitizer that survives the afternoon is sanitizer you don't have to replace.

Diagnosis, Not Guesswork

BioGuard is sold through trained specialty dealers rather than mass-market channels, and the brand backs that network with the ALEX® water analysis system. ALEX reads a full water sample — sanitizer, pH, total alkalinity, calcium hardness, cyanuric acid, metals, and more — and returns a sequenced correction plan rather than a generic product suggestion. That distinction matters more than it sounds. Cloudy water has at least six common causes, and the fix for a filtration problem is nothing like the fix for a high-pH problem or a phosphate problem. Testing tells you which one you actually have.