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BioGuard SoftSwim A | Biguanide Pool Algaecide

SKU: 22853BIO
$29.99

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Description

BioGuard SoftSwim A is the algaecide component of the SoftSwim program — BioGuard's completely chlorine-free approach to pool care. It's Step A of a three-part system, and on a biguanide pool it carries more weight than an algaecide does anywhere else.

SoftSwim is built for people who don't want chlorine in their water at all. Not less chlorine — none. The sanitizer in the program is a biguanide, a completely different class of chemistry that kills bacteria effectively while leaving water that feels soft against skin, doesn't sting eyes, doesn't strip hair, and doesn't carry the smell people associate with a treated pool. Biguanide also doesn't break down in sunlight, doesn't lose strength at high temperatures, and doesn't push pH around, so a SoftSwim pool generally needs fewer corrections through a season than a chlorine pool does.

What biguanide is not is a strong algaecide. It's an excellent bactericide, but it doesn't control algae the way a chlorine residual does — and that's precisely why the program starts with A rather than B. SoftSwim A is doing work that chlorine would otherwise be doing for free in a conventional pool, which makes staying on the weekly schedule considerably more important here than it is on a chlorine program.

The formula is a 40% quaternary ammonium algaecide that protects against a broad spectrum of algae, remains stable against UV, and works harder as water temperature rises — strongest exactly when algae pressure peaks in midsummer. At roughly pH 7.5 it won't disturb your balance, and it can be dosed weekly or every two weeks depending on how you prefer to run your routine.

One thing to be clear about before buying: SoftSwim is a closed system. Every product in a biguanide pool has to be biguanide-compatible, and chlorine and bromine are not merely discouraged — they destroy the sanitizer outright. Whether the program fits your pool is covered below.

Pro Tip: Nothing containing chlorine or bromine goes in a SoftSwim pool. Ever. Not a shock treatment, not a chlorine tablet, not a "just this once" fix on a cloudy Saturday. Chlorine and biguanide destroy each other on contact, and the result is cloudy water, a gummy residue through the filter, and a collapsed sanitizer residual that costs far more to recover than whatever problem you were trying to solve. Make sure everyone who touches the pool knows — a service tech, a house sitter, a helpful neighbor with a spare bucket of shock. And when you get water tested, say SoftSwim or biguanide before the sample goes in the machine, because the correct recommendation is completely different.

Brand

BioGuard®

What's in the Box
  • 1 x BioGuard SoftSwim A, 1 quart (32 fl oz) bottle
  • Full manufacturer label with dosing rates and safety information

One quart is a full initial application for a 25,000-gallon pool, or roughly six weeks of maintenance on a 20,000-gallon pool.

Key Features

Step A of the SoftSwim Program

The algaecide foundation of BioGuard's chlorine-free A-B-C system, formulated to work with biguanide sanitizer rather than against it.

Broad-Spectrum Algae Protection

Inhibits and controls a wide range of algae types, keeping pool water clear and free of visible growth.

Works Harder in High Temperatures

Activity increases as water warms rather than fading — which is backwards from how most people expect a chemical to behave, and exactly right for a pool, since algae grows fastest in hot water.

UV Stable, Won't Evaporate

Holds up against direct sunlight instead of dissipating, so the residual stays in the water between doses through the brightest part of the season.

Won't Affect pH

At roughly pH 7.5 the product is essentially neutral, so weekly dosing doesn't drag your balance around or trigger a correction cycle.

Contains No Chlorine or Bromine

Fully compatible with the biguanide sanitizer program, with none of the halogen chemistry the system is designed to avoid.

Flexible Schedule

Apply weekly or double the dose and apply every two weeks — whichever fits how you actually maintain the pool.

Supports the Rest of the Program

Regular use reinforces the effectiveness of the other SoftSwim products, since a pool free of algae pressure lets the sanitizer and clarifier do their own jobs.

How It Works

SoftSwim A carries two quaternary ammonium compounds — alkyl dimethyl benzyl ammonium chloride at 30% and dimethyl benzyl ammonium chloride at 10%, for 40% total active. Quats attack algae physically rather than metabolically. Each molecule has a positively charged end and a long fatty tail. Algae cell walls carry a negative surface charge, so the charged end is drawn straight to the cell and the tail embeds itself in the membrane. Enough of them lodged in the membrane and it fails structurally — the cell leaks and dies.

Because that's a mechanical failure rather than a poisoning, algae doesn't develop resistance to quats the way it can to some other treatments. And because the mechanism doesn't depend on photosynthesis being active, the residual keeps working in shade and overnight.

Understanding why the algaecide comes first in this program requires understanding what biguanide does and doesn't do. Biguanide — polyhexamethylene biguanide — is a genuinely effective bactericide. It disrupts bacterial cell membranes, and unlike chlorine it isn't consumed by sunlight, isn't degraded by heat, and doesn't shift pH. Those are real advantages and they're why the system exists.

But biguanide is a comparatively weak algaecide. In a chlorine pool, the free chlorine residual is quietly suppressing algae around the clock in addition to sanitizing; you get algae control as a side effect of sanitation. A biguanide pool doesn't get that. The algaecide has to carry the entire algae-control load by itself, which is why SoftSwim A is Step A and why a missed week matters more here than it would on a chlorine program.

The reason chlorine and biguanide can't coexist comes down to direct chemical conflict. Chlorine is a powerful oxidizer, and biguanide molecules are readily oxidized. Introduce chlorine to a biguanide pool and the chlorine destroys the sanitizer while the reaction products form a sticky, cloudy residue that fouls filter media. Both chemicals are consumed, the pool loses its sanitizer residual, and recovery usually means a full drain and refill.

Pro Tip: Confirm SoftSwim actually fits your pool before you commit to the program. BioGuard specifies it for in-ground or above-ground pools holding less than 25,000 gallons, with a bottom drain, and with excellent circulation running at least 12 hours per day. Those aren't marketing preferences — they're the conditions the program needs to work. A large pool, a pool without a main drain, or a pool on a short pump schedule will fight you all season, and switching systems afterward means draining and refilling. If your pool meets all three, SoftSwim delivers water most chlorine users never experience. If it doesn't, a chlorine or bromine program is the better call.

Directions for Use

Dosage Reference

  • Initial application: 32 fl oz per 25,000 gallons
  • Routine maintenance, weekly: 1 fl oz per 5,000 gallons
  • Routine maintenance, every two weeks: 2 fl oz per 5,000 gallons

Before You Start

  1. Confirm all pool equipment is working properly.
  2. Backwash or clean the filter system following your equipment manufacturer's directions.
  3. Adjust pH to 7.2–7.6.
  4. Check for metals. If metals are present, add a stain and scale inhibitor before treating to prevent staining of the pool surface.
  5. Confirm the pool has no chlorine or bromine residual if you are converting from a halogen program. Converting requires draining and refilling — the two chemistries cannot be blended.

Initial Application

  1. With the pump running, add 32 fl oz per 25,000 gallons directly to the pool, distributing around the perimeter.
  2. Allow the water to circulate to distribute the product.
  3. Continue with the rest of the SoftSwim start-up program per those product labels.
  4. Begin routine maintenance dosing on your chosen schedule.

Routine Maintenance

  1. Choose one schedule and stay on it: 1 fl oz per 5,000 gallons weekly, or 2 fl oz per 5,000 gallons every two weeks.
  2. Add with the pump running, distributing around the pool.
  3. Keep circulation running at least 12 hours per day throughout the season — the program depends on it.
  4. Test regularly with SoftSwim-specific test strips. Standard chlorine test kits will not read a biguanide pool correctly.
  5. Maintain SoftSwim B and SoftSwim C on their own schedules alongside this product.

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 well away from any chlorine or bromine products
  • Keep out of reach of children and pets
  • Read and follow all label precautions, first aid, and disposal directions before use

Pro Tip: Don't skip a week on a biguanide pool. On a chlorine program, a forgotten algaecide dose is usually forgiven because the chlorine residual is suppressing algae in the background anyway. SoftSwim has no such safety net — biguanide is a strong bactericide but a weak algaecide, so this product is the only thing standing between your pool and an algae bloom. Recovering algae in a biguanide pool is also harder and more expensive than in a chlorine pool, because the fast, cheap fix everyone else reaches for is exactly the one you can't use. Put the dose on a recurring calendar reminder and treat it as non-optional.

Specifications
  • Brand: BioGuard
  • Product Type: Quaternary ammonium algae inhibitor and preventative
  • Form: Liquid
  • Volume: 1 quart (32 fl oz)
  • Manufacturer Part Number: 22853BIO
  • Active Ingredient 1: Alkyl dimethyl benzyl ammonium chloride, 30%
  • Active Ingredient 2: Dimethyl benzyl ammonium chloride, 10%
  • Other Ingredients: 60%
  • Total Active: 40% quaternary ammonium
  • Product pH: Approximately 7.5
  • Chlorine Content: None
  • Bromine Content: None
  • Initial Dose: 32 fl oz per 25,000 gallons
  • Weekly Dose: 1 fl oz per 5,000 gallons
  • Biweekly Dose: 2 fl oz per 5,000 gallons
  • Target pH Before Use: 7.2–7.6
  • UV Stability: Stable in sunlight; will not evaporate
  • Temperature Behavior: Activity increases as water temperature rises
  • System Role: Step A of the BioGuard SoftSwim program
  • Required Companion Products: SoftSwim B bactericide and SoftSwim C clarifier
  • Program Pool Limit: Less than 25,000 gallons, with a bottom drain and 12+ hours daily circulation
  • Testing: Requires SoftSwim-specific test strips
  • Not Compatible With: Chlorine, bromine, or salt chlorine generators
  • Shipping Classification: DOT-regulated — ground shipping only
Compatibility

The SoftSwim A-B-C System

  • SoftSwim A — algaecide; prevents and controls algae growth. This product.
  • SoftSwim B — bactericide; the biguanide sanitizer that does the disinfecting.
  • SoftSwim C — clarifier; removes body oils, cosmetics, hair products, and other contaminants the sanitizer doesn't address.

All three are required. SoftSwim A is not a sanitizer and cannot run a pool on its own.

Pool Requirements for the SoftSwim Program

  • In-ground or above-ground pools holding less than 25,000 gallons
  • Pools that have a bottom drain
  • Pools with excellent circulation, with the pump operating at least 12 hours per day

Pool Surfaces

  • Plaster and gunite
  • Vinyl liner
  • Fiberglass
  • Painted surfaces

Critical Incompatibilities

  • Chlorine, in any form. No tablets, granules, shock, liquid chlorine, or chlorine-based algaecide. Chlorine and biguanide destroy each other.
  • Bromine, in any form. Same conflict as chlorine.
  • Salt chlorine generators. A salt system produces chlorine, which makes it fundamentally incompatible with a biguanide program.
  • Mineral systems and copper algaecides. Verify compatibility with your dealer before adding any metal-based product to a biguanide pool.
  • Non-chlorine shock made for chlorine pools. Biguanide pools use their own oxidizer at their own rate — confirm the product is labeled for biguanide systems.
  • Never mix with any other chemical in a bucket, skimmer, or feeder. Add products separately with circulation between additions.

Filtration Notes

Biguanide programs tend to leave a residue in filter media over time, so plan on cleaning the filter more often than a chlorine pool would require. Use a filter cleaner appropriate to your media, and never let any filter cleaner return to the pool.

What It Does Not Do

  • Not a sanitizer. Provides no disinfection. SoftSwim B is required.
  • Not a clarifier or oxidizer. SoftSwim C handles contaminant removal.
  • Not a substitute for brushing. Established algae must be physically disturbed for treatment to reach it.

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.