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BioGuard Smart Shield 1 Qt. | Liquid Pool Cover

SKU: 23762BIO
$33.99

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Description

BioGuard Smart Shield is a liquid pool cover. It forms an invisible barrier on the water surface that reduces evaporation — conserving water and preserving heat — and a single application lasts up to 30 days.

Evaporation is a bigger drain than most pool owners realize, and it costs money two ways at once. The obvious one is water: an uncovered pool can lose a substantial volume over a hot, dry month, and every gallon you replace also dilutes your chemistry and has to be rebalanced. The less obvious one is heat. Evaporation is the single largest route by which a pool loses warmth — far more than conduction through the walls or radiation to the night sky. Every gallon that evaporates carries a large amount of energy out of the pool with it.

That's why a heated pool without a cover is expensive to run. The heater spends much of its output replacing warmth that's leaving through the surface, all night, every night.

A solid or solar cover solves this well — and nobody uses one consistently, because hauling a cover on and off a pool is genuinely inconvenient. Smart Shield does a meaningful share of the same job with no cover to handle at all. You pour it in once a month and it works continuously, including overnight when heat loss is highest and nobody's around to put a cover on.

It's invisible in the water, doesn't interfere with swimming, and needs no equipment. Dosing is simple at 8 fl oz per 15,000 gallons monthly, and a single quart covers four months on a 15,000-gallon pool.

Pro Tip: This product earns its keep fastest on a heated pool in a dry climate. Evaporation is the dominant heat-loss mechanism in any pool, and it accelerates sharply when the air is dry, the wind is up, and nights are cool — conditions that describe most of the Intermountain West through the entire swim season. If you heat your pool, the gas or electricity you're spending overnight is largely replacing warmth that left through the surface, and a liquid cover addresses that every night without anyone having to remember anything. On an unheated pool the water savings still matter, but the payback is slower.

Brand

BioGuard®

What's in the Box
  • 1 x BioGuard Smart Shield, 1 quart (32 fl oz) bottle
  • Full manufacturer label with dosing rates and application directions

At 8 fl oz per 15,000 gallons monthly, a quart delivers four monthly applications for a 15,000-gallon pool — most of a swim season. A 30,000-gallon pool uses 16 fl oz per month, so a quart covers two months.

Key Features

Reduces Water Evaporation

Cuts the water you lose to the air, which means less topping off, a lower water bill, and less chemistry diluted by fresh fill water.

Preserves Water Temperature

Evaporation is the largest single route by which a pool loses heat. Slowing it keeps warmth in the water instead of sending it into the night air.

A Single Application Lasts Up to 30 Days

One pour per month rather than a daily or weekly task, and it works continuously in between — including overnight, when heat loss peaks.

Works Without a Physical Cover

All the convenience a solid or solar cover doesn't have. Nothing to haul, roll, store, or wrestle with at the end of a long day.

Invisible in the Water

No visual change to the pool and no interference with swimming, diving, or water features.

Simple Monthly Application

Shake, pour in front of the return lines with the pump running, and you're done. No mixing, no equipment, no measuring beyond the dose.

Scales to Any Pool Size

Dosed by volume or by surface area, so it works on standard residential pools and larger installations alike.

How It Works

Smart Shield works by forming an extremely thin layer across the surface of the water — a monolayer, effectively one molecule thick. It's invisible, it doesn't affect how the water feels, and it self-heals: when swimmers break it up, it reforms once the surface settles.

That layer slows the rate at which water molecules escape into the air. It doesn't stop evaporation entirely, but it reduces it substantially — and the consequences of that reduction are larger than the water savings alone suggest.

Here's why the heat benefit is the bigger one. Evaporation is a cooling process, and a powerful one. When a water molecule leaves the surface as vapor, it takes a considerable amount of energy with it — the same principle that makes sweating effective. In a swimming pool, evaporative loss accounts for the majority of total heat loss, well ahead of conduction through the shell or radiation to the sky. Slowing evaporation is therefore the single most effective way to keep a pool warm.

The conditions that drive evaporation are worth knowing, because they explain when this product matters most:

  • Dry air — the lower the humidity, the faster water leaves the surface. Arid climates see dramatically higher evaporation than humid ones.
  • Wind — moving air carries away the humid layer sitting just above the water, resetting the gradient and accelerating loss.
  • Temperature difference — a warm pool under cool night air evaporates fastest, which is why heated pools lose the most and why nights are the worst period.
  • Surface area — evaporation happens at the surface, which is why the label offers a dosing option based on square footage.

The 30-day duration reflects gradual depletion. The layer is consumed and dispersed over time through wind, swimmer activity, filtration, and normal degradation, so monthly reapplication maintains it.

One honest note on scope: Smart Shield is not a sanitizer, balancer, or clarifier, and it doesn't replace a physical cover for winterizing or for keeping debris out. It addresses evaporation and the heat that leaves with it — nothing else.

Pro Tip: Add it in front of the return lines and keep the pump on a daily schedule — both instructions are on the label and both matter for the same reason. The product has to spread evenly across the entire surface to work, and the returns are what push it outward from where you poured it. Dumping it in one corner of a still pool leaves you with a partially covered surface and a partial result. Run the pump daily for proper circulation, and if your pool has a spillover or waterfall, expect the layer to break up faster in that area — heavy aeration works against surface films.

Directions for Use

Dosage Reference

  • Standard: 8 fl oz per 15,000 gallons of water
  • Larger pools: 16 fl oz per 1,000 sq ft of surface area, or per 30,000 gallons of pool water, once per month
  • Both rates work out the same — roughly 8 fl oz per 15,000 gallons monthly

Quantity by Pool Size

  • 15,000 gallons: 8 fl oz per month — one quart lasts four months
  • 20,000 gallons: about 11 fl oz per month — one quart lasts about three months
  • 30,000 gallons: 16 fl oz per month — one quart lasts two months

Application

  1. Shake the bottle before using.
  2. With the pump running, add 8 fl oz per 15,000 gallons of water.
  3. For best dispersion, add Smart Shield in front of the pool return lines.
  4. Run the pump daily for proper circulation.
  5. Reapply once per month — a single application lasts up to 30 days.

Getting the Most From It

  • Apply on a calm day if you can — a settled surface lets the layer establish evenly
  • Keep circulation running on its normal daily schedule
  • Expect faster breakdown around waterfalls, spillovers, and heavily jetted returns
  • Reapply on schedule rather than waiting to notice a difference; the effect is gradual and easy to miss until it's gone
  • Pair with a physical cover where practical — the liquid cover handles the nights the physical one doesn't get used

When It Matters Most

  • Through the hottest, driest stretch of summer
  • On heated pools, all season
  • During windy periods
  • When nights are cool and days are warm — the largest temperature gradient
  • Any time you're topping the pool off more often than you'd like

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: Track your top-off frequency for a month before and after, because the benefit is otherwise invisible. Unlike a clarifier or an algaecide, this product doesn't produce a visible change — nothing looks different, so it's easy to conclude nothing happened. What you can measure is how often you're running the hose and, on a heated pool, what the gas bill does. Note the water line on the skimmer at the start of a stretch of hot weather, check it a week later, then apply Smart Shield and repeat the observation. That's the comparison that tells you whether it's worth the monthly reorder for your pool, your climate, and your equipment.

Specifications
  • Brand: BioGuard
  • Product Type: Liquid pool cover and evaporation reducer
  • Form: Liquid
  • Volume: 1 quart (32 fl oz)
  • Manufacturer Part Number: 23762BIO
  • Functions: Reduces water evaporation; preserves water temperature
  • Standard Dose: 8 fl oz per 15,000 gallons
  • Large Pool Dose: 16 fl oz per 1,000 sq ft of surface area, or per 30,000 gallons
  • Duration: A single application lasts up to 30 days
  • Frequency: Once per month
  • Application Method: Shake, then add in front of the pool return lines with the pump running
  • Circulation: Run the pump daily for proper circulation
  • Visibility: Invisible in the water; does not interfere with swimming
  • Coverage per Bottle: Four monthly applications for a 15,000-gallon pool
  • Sanitizer Compatibility: Chlorine, bromine, salt generator, and mineral systems
  • Suitable Surfaces: Plaster, gunite, vinyl liner, fiberglass, painted
  • Not A Substitute For: A sanitizer, a winter cover, a debris cover, or a heater
  • Shipping Classification: DOT-regulated — ground shipping only
Compatibility

Pool Types and Surfaces

  • In-ground and above-ground pools
  • Plaster, gunite, vinyl liner, fiberglass, and painted surfaces
  • Sand, cartridge, and DE filtration

Sanitizer Programs

  • Compatible with chlorine, bromine, salt chlorine generator, and mineral system pools

Where It Delivers the Most Value

  • Heated pools — the clearest case, since evaporation is where most of your heating dollars go
  • Dry climates — low humidity drives evaporation hard, and much of the Intermountain West qualifies all season
  • Windy locations — exposed pools without windbreaks lose water and heat considerably faster
  • Pools without a cover, or where the cover rarely gets used in practice
  • Areas with water restrictions or high water costs
  • Pools that need frequent topping off through the season

Liquid Cover Versus a Physical Cover

  • A solar or solid cover reduces evaporation more completely and also blocks debris and, in the case of solar covers, adds heat gain. It's the more effective option when it's actually on the pool.
  • Smart Shield reduces evaporation less completely but works continuously with no handling at all — which in practice often means more total coverage over a season than a cover that stays rolled up on the deck.
  • They aren't mutually exclusive. A liquid cover fills the gap on the nights and weeks the physical cover doesn't get used.
  • Neither replaces a winter cover for closing a pool.

What It Does Not Do

  • Not a sanitizer, balancer, or clarifier. It affects surface evaporation only.
  • Not a debris barrier. Leaves and dirt still land in the pool.
  • Not a substitute for a winter cover. Closing a pool requires a physical cover.
  • Not a heater. It slows heat loss; it doesn't add warmth.

Important Handling Cautions

  • Shake the bottle before using.
  • Never mix with other chemicals. Add products separately with circulation between additions.
  • Run the pump daily for proper circulation.

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.