BioGuard SilkGuard Complete 3" Tabs | Sanitizer

SKU:
From $44.99

Check Discount Eligibility
Returns On Hazardous Materials
Size

Description

BioGuard SilkGuard Complete 3" Chlorinating Tablets are the sanitizing foundation of the BioGuard 3-Step Care System — and they do considerably more than hold a chlorine residual. Where a commodity trichlor tablet delivers chlorine and nothing else, SilkGuard Complete layers three proprietary technologies and a copper-based algae component into the same tablet.

The result is a sanitizer that addresses four problems at once. SilkGuard® Technology attaches to hard water minerals and metal surfaces, which softens the feel of the water while protecting the pool surface and equipment from scale, corrosion, and staining. SmartGuard® Technology controls how quickly the tablet dissolves, so it lasts longer than a conventional trichlor tab and behaves predictably across every pump type, including variable-speed. SunShield® Technology protects the chlorine residual from ultraviolet degradation, which is the largest single source of chlorine loss in an outdoor pool. And algae-killing crystals add a copper-based preventative to every tablet, so algae control is happening continuously rather than only when you remember to dose an algaecide.

That combination matters most in hard water. Scale on a heater element is expensive, staining on a plaster surface is difficult to reverse, and corrosion in the equipment pad is worse than either. A sanitizer that actively works against all three while it chlorinates is doing several jobs on one line item.

The 3" tablet format is designed for every common application method — skimmer, in-line or off-line feeder, or floater. SmartGuard's controlled dissolution is specifically what makes skimmer use practical, which is not true of every trichlor tablet on the market. Available in 3.5 lb and 7.5 lb containers.

Pro Tip: Never put any other chemical into the same skimmer, feeder, or floater where these tablets are in use. Mixing trichlor with another pool chemical — particularly calcium hypochlorite shock — in a confined space can cause a fire or explosion. This is not a cautious disclaimer; it is a documented and recurring cause of equipment fires. One product per device, and rinse a feeder thoroughly before switching product types.

Brand

BioGuard®

What's in the Box
  • 1 x BioGuard SilkGuard Complete 3" Chlorinating Tablets container, in your selected size
  • Full manufacturer label with dosing rates, startup directions, and safety information

Each 3" tablet weighs approximately 8 oz, so the standard 16 oz dose is roughly two tablets.

Key Features

SilkGuard Technology — Softer Water, Protected Surfaces

Bonds to hard water components and metal surfaces to soften how the water feels against skin while shielding the pool finish and equipment from scale formation, corrosion, and metal staining. Pool owners in hard water areas notice the difference in feel first and in their heater's condition later.

SmartGuard Technology — Controlled, Longer-Lasting Dissolution

Regulates how quickly each tablet breaks down, extending tablet life compared to conventional trichlor and delivering a steadier residual instead of a spike-and-fade cycle. The dissolution rate is optimized for all pump types, including variable-speed systems.

SunShield Technology — UV Protection for Your Chlorine

Shields the free chlorine residual from ultraviolet breakdown. Unprotected chlorine can lose a substantial share of its strength in a single sunny afternoon, so protecting the residual directly reduces how much sanitizer the pool consumes over a season.

Algae-Killing Crystals

A copper-based algae preventative built into every tablet, working continuously to stop algae before it establishes rather than treating it after a bloom is visible.

Works in Skimmers, Feeders, and Floaters

Designed for all three application methods. The controlled dissolution rate is what makes skimmer application viable, which sets it apart from tablets that must be restricted to a feeder or floater.

84% Available Chlorine

A concentrated trichlor formulation that delivers a strong, stabilized residual from a compact tablet, keeping the volume of product you handle and store to a minimum.

Step 1 of the BioGuard 3-Step Care System

The sanitizing foundation the rest of the program is built on, formulated to work alongside BioGuard's shock and algaecide products rather than compete with them.

Two Container Sizes

Available in 3.5 lb and 7.5 lb, so you can match your purchase to pool volume and season length instead of storing chlorine you won't use before it loses strength.

How It Works

The primary active ingredient is trichloro-s-triazinetrione — trichlor — at 91.57%, yielding 84% available chlorine. As water passes over the tablet, the trichlor dissolves gradually and releases hypochlorous acid, the active form of chlorine that destroys bacteria and other microorganisms by disrupting their cell structure.

Trichlor is a stabilized chlorine source, meaning it contributes cyanuric acid to the water as it dissolves. Cyanuric acid functions as sunscreen for free chlorine, slowing UV breakdown so each tablet's chlorine stays active longer. SunShield Technology builds on that principle. The tradeoff is that stabilizer accumulates permanently — it doesn't evaporate, burn off, or filter out.

SmartGuard governs the physical dissolution rate. Rather than releasing chlorine as fast as water contact allows, the tablet meters itself out, which extends its life and evens out the residual between refills. It's also the reason the tablet behaves consistently whether it sits in a high-flow skimmer or a slow-moving floater, and why variable-speed pumps don't throw the dosing off.

SilkGuard works through a different mechanism entirely — sequestration. Its active components bind to dissolved calcium, metals, and other hard water minerals, holding them in solution so they can't precipitate onto the pool surface as scale or deposit as stains. The same binding action creates a protective effect on metal equipment surfaces, reducing corrosion, and it's what produces the softer feel swimmers notice.

The copper sulfate pentahydrate component, equal to 0.25% metallic copper, releases copper ions steadily as the tablet dissolves. Copper interferes with algae cell metabolism directly, giving the tablet an algae-control mechanism that chlorine alone doesn't provide.

One property worth understanding: trichlor is strongly acidic, with a solution pH well below 3. Continuous tablet use pulls pH and total alkalinity downward over the season, which is normal and expected but has to be corrected rather than ignored.

Pro Tip: Never throw tablets directly into the pool. A tablet resting on the floor creates an intensely acidic, highly concentrated spot of chlorine right against the surface, and the mark it leaves is permanent — bleaching on a vinyl liner, etching on plaster, and staining on colored finishes. Tablets belong in a skimmer, feeder, or floater where flowing water dilutes them immediately. The same rule applies to a tablet that's slipped out of a floater: retrieve it right away rather than letting it finish dissolving where it landed.

Directions for Use

Dosage Reference

  • Start-up: 16 oz (approximately 2 tablets) per 10,000 gallons
  • Routine maintenance: 16 oz (approximately 2 tablets) per 10,000 gallons per week, or as needed
  • Target free available chlorine: 1–4 ppm at all times

Before You Start

  1. Confirm all pool equipment is operating properly.
  2. Clean or backwash the filter per your equipment manufacturer's directions.
  3. Adjust pH to 7.2–7.6.
  4. Add stabilizer as needed to establish a minimum cyanuric acid level of 30–40 ppm, which reduces UV loss of the chlorine residual.
  5. If the water is cloudy or green, superchlorinate with an appropriate shock product and get the pool clear before starting tablet feeding. Tablets maintain a residual; they don't recover a failed pool.

Start-Up and Ongoing Feeding

  1. Add 16 oz of product (approximately 2 tablets) per 10,000 gallons of pool water to your skimmer, feeder, or floater.
  2. Adjust the feeder or floater per its manufacturer's instructions to establish a free available chlorine level of 1–4 ppm.
  3. Allow the water to circulate at least 4 hours, then test the free available chlorine level.
  4. Once free chlorine is holding at 1–4 ppm, add the preventative algaecide appropriate to your pool.
  5. Reload weekly, or as needed, at the same rate to hold the residual.
  6. Check the skimmer, feeder, or floater often and refill before it runs empty. Sunlight, rainfall, water temperature, bather count, and how often the pool is used all change how fast the residual is consumed, so refill intervals will shift through the season.

Safety Requirements

  • Do not add any other chemical into the skimmer, feeder, or floater while this product is in use. Fire or explosion may result.
  • Do not throw tablets directly into the pool. Direct contact will damage pool surfaces and materials.
  • Re-entry into the pool is prohibited when free available chlorine exceeds 4 ppm, due to risk of bodily injury. Test before swimmers enter.
  • When using other products alongside this one, follow the directions on those labels as well.

Storage and Handling

  • Store in a cool, dry, well-ventilated area away from direct sunlight, heat, and open flame
  • Keep the container tightly closed and the product completely dry — moisture releases chlorine gas
  • Store separately from other pool chemicals, especially calcium hypochlorite shock, acids, and organic materials
  • Keep out of reach of children and pets
  • Never return a used or wet tablet to the original container
  • Read and follow all label precautions, first aid, and disposal directions before use

Pro Tip: Test cyanuric acid mid-season, not just at opening. Every trichlor tablet adds stabilizer permanently, and a pool fed continuously all summer can drift far above the 30–40 ppm target without anyone noticing. Once cyanuric acid climbs past roughly 100 ppm, free chlorine becomes progressively less effective at the same test reading — the pool looks properly chlorinated and behaves like it isn't. Watch pH and total alkalinity too, since trichlor is strongly acidic and continuous feeding pulls both downward. A pool that "stopped holding chlorine" in August is usually stabilizer-locked, and no amount of additional product will fix it. Dilution will.

Specifications
  • Brand: BioGuard
  • Product Type: Multi-benefit chlorinating tablets
  • Form: 3" slow-dissolving tablets
  • Available Sizes: 3.5 lb and 7.5 lb
  • Approximate Tablet Weight: 8 oz each
  • Active Ingredient: Trichloro-s-triazinetrione, 91.57%
  • Secondary Active: Copper sulfate pentahydrate, 0.99% (equal to 0.25% metallic copper)
  • Other Ingredients: 7.44%
  • Available Chlorine: 84%
  • Stabilized: Yes — contributes cyanuric acid to the water
  • Proprietary Technologies: SilkGuard, SmartGuard, and SunShield
  • Algae Control: Copper-based algae-killing crystals
  • Start-Up Dose: 16 oz (about 2 tablets) per 10,000 gallons
  • Maintenance Dose: 16 oz (about 2 tablets) per 10,000 gallons weekly, or as needed
  • Target Free Chlorine: 1–4 ppm
  • Target pH: 7.2–7.6
  • Minimum Stabilizer Level: 30–40 ppm
  • Application Methods: Skimmer, in-line or off-line feeder, or floater
  • Pump Compatibility: All types, including variable-speed
  • Suitable Surfaces: Plaster, gunite, vinyl liner, fiberglass, painted
  • Not For Use In: Biguanide pools, spas, or hot tubs
  • System Role: Step 1 of the BioGuard 3-Step Care System
  • Shipping Classification: DOT-regulated — ground shipping only
Compatibility

Application Methods

  • Skimmers — supported, and specifically what SmartGuard's controlled dissolution was optimized for
  • In-line and off-line chlorine feeders — supported; adjust output to hold the target residual
  • Floating dispensers — supported; adjust the vent setting to hold the target residual

Pool Types and Surfaces

  • In-ground and above-ground pools of any size
  • Plaster, gunite, vinyl liner, fiberglass, and painted surfaces
  • All pump types, including single-speed, two-speed, and variable-speed
  • Sand, cartridge, and DE filtration

Water Care Programs

  • Traditional chlorine pools — this is the intended application and Step 1 of the 3-Step Care System
  • Salt chlorine generator pools — can supplement generator output during heavy demand or cell downtime, though continuous use will raise stabilizer levels; check your generator manufacturer's guidance first

Important Incompatibilities

  • Biguanide (non-chlorine) pools — do not use. Chlorine and biguanide chemistry destroy each other, resulting in cloudy water, filter fouling, and a failed sanitizer residual.
  • Spas and hot tubs — this is a pool product. Trichlor tablets are too aggressive and too acidic for the small, hot volume of a spa. Use a spa-specific sanitizer.
  • Never combine with other chemicals in a feeder, floater, or skimmer. Mixing trichlor with another product — calcium hypochlorite shock above all — in a confined space can cause fire or explosion.
  • Not compatible with pools already at high cyanuric acid. Every tablet adds more. If stabilizer is already elevated, an unstabilized chlorine source is the better choice until levels come down through dilution.

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.