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BioGuard Kleen It 1 Qt. | Pool Filter Cleaner

SKU: 23758BIO
$20.99

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Description

BioGuard Kleen It is an acidic filter cleaner that dissolves the mineral side of filter fouling — scale, rust, metal deposits, and hardened clarifier residue that no amount of rinsing or backwashing will remove.

Filter media gets dirty in two fundamentally different ways, and this is the distinction most pool owners never learn. One kind of fouling is organic: body oils, sunscreen, lotions, and the greasy film they leave behind. The other is mineral: calcium scale precipitating out of hard water, iron and copper depositing from fill water or corroding equipment, and clarifier residue building into a crust. Those two require completely different chemistry to remove. A degreaser will not dissolve calcium. An acid will not lift oil.

Kleen It handles the mineral half. At a pH of 1.0 it's a genuine acid cleaner, strong enough to break apart scale that has been building for seasons and release metal staining from filter media — while still being safe on the filter equipment itself, across sand, cartridge, and DE systems alike. It works by spray or by soak, so you can do a quick maintenance clean in fifteen minutes or run an overnight soak on elements that have been neglected.

The payoff is measured in flow. Scale on filter media restricts water passage the same way it restricts a heater element, which drives operating pressure up, shortens filter cycles, forces the pump to work harder, and quietly reduces how much water actually gets filtered per day. Clearing it brings pressure back toward baseline and returns the filter to the performance it had when it was new. Used once or twice a season, it meaningfully extends the working life of the media — and a cartridge set costs considerably more than a bottle of cleaner.

It also works beyond the filter. The same formula cleans spa surfaces, pool equipment, outdoor furniture, and vinyl, plastic, and rubber surfaces, and it carries a fresh citrus scent rather than the sharp acid smell you'd expect.

Pro Tip: A truly dirty filter needs two cleaners, in this order: degrease first, descale second. Strip the oil and grease with BioGuard Strip-Kwik, rinse thoroughly, then treat with Kleen It for scale and metals. Doing it in reverse wastes the acid, because it can't reach mineral deposits through a coating of body oil. Never mix the two products or combine them in the same soak — run them as separate steps with a complete rinse between. Most cartridges people write off as worn out were only ever getting half of a two-part cleaning.

Brand

BioGuard®

What's in the Box
  • 1 x BioGuard Kleen It Filter Cleaner, 1 quart (32 fl oz) bottle
  • Full manufacturer label with application directions and safety information

BioGuard no longer ships this product with a trigger nozzle. For spray application, transfer the product to a clean spray bottle used for nothing else.

Key Features

Removes Scale, Metals, and Rust

Dissolves the calcium scale, iron and copper deposits, rust, and hardened clarifier residue that build up in filter media over time. This is the fouling that rinsing and backwashing cannot touch.

Dual-Action Formula

Targets both mineral scale and the dirt and debris trapped alongside it, clearing the media without leaving residue behind.

Safe on All Filter Types

Proven not to damage filter equipment across sand, cartridge, and DE systems. One product covers every filter in the lineup.

Spray or Soak Application

Spray full strength for a fast clean in five to ten minutes, extend to an hour for heavily soiled elements, or run an overnight dilute soak for media that's badly scaled. The method scales to how bad the problem is.

Restores Filter Performance

Clearing mineral buildup restores flow through the media, brings operating pressure back down toward baseline, lengthens filter cycles, and improves water clarity by letting the filter do its job again.

Extends Filter Media Life

Scale that's allowed to accumulate season after season eventually makes a cartridge or a sand bed unrecoverable. Cleaning it out on schedule postpones a replacement that costs many times more than the cleaner.

Also Cleans Surfaces Beyond the Filter

Effective on spa surfaces, pool equipment, outdoor furniture, and vinyl, plastic, and rubber surfaces — useful anywhere mineral deposits collect around the pool area.

Fresh Citrus Scent

Considerably more pleasant to work with than the sharp chemical smell most acid cleaners carry.

How It Works

Kleen It is an acidic cleaner with a pH of 1.0, and that number is the entire mechanism. Scale is primarily calcium carbonate, a mineral that is essentially insoluble in neutral water — which is exactly why it survives every backwash you run. In acid, it isn't insoluble at all. The acid reacts with the carbonate, breaks it apart, and converts it into soluble compounds that rinse away with plain water.

The same reaction releases metal deposits. Iron and copper that have precipitated onto filter media from fill water, corroding equipment, or mineral treatments are held in place as oxides and mineral salts. Acid dissolves those too, which is why the label lists rust and metal removal alongside scale.

Hardened clarifier residue responds for a related reason. Clarifiers work by gathering fine particles into filterable masses, and over time that captured material can compact into a crust bound together with mineral deposits. Dissolving the mineral binder releases the trapped debris along with it.

What acid does not do is remove oil. Body oils, sunscreen, and lotions are non-polar organic compounds; they aren't minerals, they don't react with acid, and they'll sit on the media untouched while the acid works around them. Removing oil requires surfactants, which is a different product entirely. This is the single most important thing to understand about filter cleaning, and it's why BioGuard sells a degreaser and a descaler as two separate items rather than one.

The two application methods differ in concentration and contact time, not chemistry. Spray application puts the acid on at full strength for a short window — five to ten minutes normally, up to an hour on heavy soil. The overnight soak dilutes the product substantially, at 32 oz into 5 gallons of water, and compensates with many hours of contact. Deep scale in the folds of a pleat responds better to long exposure than to high concentration.

In a sand filter, the media can't be removed, so the product is drawn into the tank through the skimmer and left to sit with the pump off for an hour. The backwash that follows is the removal step — everything the acid dissolved is still inside the tank until it's flushed to waste.

Pro Tip: Remove chlorine tablets from the skimmer before you pour anything, and shut off any automatic feeder. Acid at pH 1.0 in contact with chlorine releases chlorine gas, and a skimmer housing is exactly the kind of enclosed space where that becomes dangerous rather than merely unpleasant. The same rule applies to storage: keep this bottle well away from your chlorine, never combine it with another pool chemical in a bucket or sprayer, and use a spray bottle dedicated to this product alone. Wear eye protection and gloves — this is a real acid, not a household cleaner.

Directions for Use

Application Reference

  • Spray application: full strength, undiluted
  • Standard spray dwell: 5–10 minutes
  • Heavily soiled spray dwell: up to 1 hour
  • Overnight soak solution: 32 fl oz per 5 gallons of water
  • Sand filter treatment: entire bottle poured into the skimmer
  • Recommended frequency: at least once per season; twice for non-backwashable DE and cartridge filters, mid-summer and again in fall

Non-Backwashable DE and Cartridge Filters

  1. Turn the pump off and relieve pressure at the air relief valve before opening the filter housing.
  2. Remove the elements and rinse off loose dirt with a garden hose, working between the pleats.
  3. Apply the product by spraying it directly onto the filter elements at full strength.
  4. If needed, lightly brush heavy grease spots with a soft brush. Do not use a wire or metal brush.
  5. Let the wet elements sit for 5 to 10 minutes. For heavily soiled filters, allow them to sit for 1 hour.
  6. Rinse the elements thoroughly with full-strength water from a garden hose.
  7. Reassemble the filter and resume normal operation. Note the new operating pressure as your fresh clean baseline.

Overnight Soak Alternative

  1. In a clean plastic container large enough to fully submerge the elements, prepare a solution of 32 fl oz of Kleen It per 5 gallons of water.
  2. Soak the filter elements overnight.
  3. Rinse the elements thoroughly with full-strength water from a garden hose.
  4. Reassemble the filter and resume normal operation.

Sand Filters and Some DE Filters

  1. Backwash the filter thoroughly.
  2. Turn the pump off.
  3. Remove all chlorinating product from the skimmer basket before adding this product.
  4. Turn off any automatic feeder before adding this product.
  5. Pour the entire bottle into the skimmer.
  6. Turn the pump on only until it primes and the product moves into the filter, then turn the pump off.
  7. Leave the filter selector in the backwash position or the closed position.
  8. Wait 1 hour.
  9. Turn the pump on with the selector in the backwash position and backwash until the waste water runs clear.
  10. Do not allow the product to return to the pool. Backwash to waste only.

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 chlorine products, oxidizers, and alkaline chemicals
  • Keep out of reach of children and pets
  • Wear eye protection and chemical-resistant gloves when handling
  • Use a clean, dedicated spray bottle and soaking container — never one that has held another pool chemical
  • Read and follow all label precautions, first aid, and disposal directions before use

Pro Tip: The fall cleaning matters more than the mid-summer one. A filter that goes into storage with scale and debris still in it spends the entire off-season with those deposits drying, hardening, and bonding to the media — and what would have rinsed off in October can be permanently set by April. Clean the filter as part of your closing routine, not just your opening routine. If you're storing cartridges out of the tank, let them dry completely first; dried organic residue releases more easily on the next cleaning than film that stayed damp all winter.

Specifications
  • Brand: BioGuard
  • Product Type: Acidic filter cleaner and descaler
  • Form: Liquid
  • Volume: 1 quart (32 fl oz)
  • Manufacturer Part Number: 23758BIO
  • Solution pH: 1.0
  • Scent: Fresh citrus
  • Filter Compatibility: Sand, cartridge, and DE
  • Removes: Scale, metals, rust, clarifier deposits, dirt, and debris
  • Does Not Remove: Oil, grease, and suntan lotion — use a degreaser separately
  • Spray Application: Full strength, 5–10 minute dwell, up to 1 hour for heavy soil
  • Soak Solution: 32 fl oz per 5 gallons of water, overnight
  • Sand Filter Dose: Entire bottle into the skimmer
  • Sand Filter Contact Time: 1 hour with the pump off
  • Removal Method: Rinse with fresh water, or backwash to waste for sand filters
  • Recommended Frequency: At least once per season; twice for non-backwashable DE and cartridge filters
  • Also Cleans: Spa surfaces, pool equipment, outdoor furniture, vinyl, plastic, and rubber
  • Do Not Combine With: Chlorine products or any other pool chemical
  • Packaging Note: No longer supplied with a trigger nozzle
  • Shipping Classification: DOT-regulated — ground shipping only
Compatibility

Filter Types

  • Cartridge filters — spray or soak with elements removed from the housing
  • DE (diatomaceous earth) filters — spray or soak on grids and elements; non-backwashable DE units follow the cartridge procedure
  • Sand filters — in-tank treatment through the skimmer, followed by backwashing to waste

Other Surfaces

  • Spa surfaces
  • Pool equipment
  • Outdoor furniture
  • Vinyl, plastic, and rubber surfaces

Pool Types

  • In-ground and above-ground pools
  • Chlorine, bromine, salt chlorine generator, and mineral system pools

What It Does Not Do

  • Does not remove oil, grease, or suntan lotion. Organic fouling requires a surfactant-based degreaser as a separate step. Kleen It handles minerals only.
  • Not a water treatment. This cleans filter media and surfaces; it is not added to pool water as a chemical treatment.

Critical Safety Incompatibilities

  • Never allow contact with chlorine products. Remove chlorine tablets from the skimmer basket and shut off any automatic feeder before adding this product. Acid and chlorine together release chlorine gas.
  • Never mix with any other chemical in a bucket, sprayer, skimmer, or feeder — including other filter cleaners.
  • Store separately from chlorine, oxidizers, and alkaline products.
  • Check your filter manufacturer's guidance before cleaning specialty, coated, or reinforced media, since some elements carry their own restrictions on acid cleaners.
  • Avoid prolonged contact with polished metal, natural stone, and grouted surfaces, which acid can etch.

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.