BioGuard Arctic Blue Algae Protector | Winterizer

• 1 x BioGuard Arctic Blue Algae Protector, 1 quart (32 fl oz) bottle
• Full manufacturer label with dosing rate and application directions

Note on coverage: BioGuard's Arctic Blue Winter Kit for 24,000 gallons contains one quart of this product, which puts the rate at roughly 16 fl oz per 12,000 gallons. Confirm the figure on your current bottle before dosing, and order accordingly if your pool is larger.

Prevents All Types of Pool Algae

Guards against green, mustard, and black algae through the off season, when no sanitizer residual is being maintained.

Works Through the Entire Winter

Formulated for a single closing application that holds protection across months of no circulation and no testing.

Maintains Water Clarity While Closed

Helps keep water clear under the cover rather than letting it go dull and green over the winter.

For Clear Water at Spring Opening

The whole point of the product — pulling the cover off a pool that's ready for cleanup rather than recovery.

Non-Staining

Won't leave surface staining on plaster, vinyl, or fiberglass over a long dormant period.

No Mixing or Pre-Dissolving Needed

Pours directly from the bottle into the pool — no bucket, no measuring container, no handling liquids in cold weather.

For Chlorinated or Brominated Pools

Compatible with both sanitizer programs, and with all pool surface and filter types.

Step Two of the Arctic Blue Closing Sequence

Designed to follow the winter shock and precede the closing treatment, as part of a complete winterization.

Understanding why a pool needs a dedicated winter algaecide starts with what happens after you close it.

During the season, algae is held back by two things working together: an active sanitizer residual and continuous circulation that carries chemistry to every corner of the pool. Take both away and the picture changes completely.

A closed pool loses its sanitizer residual within weeks. Chlorine is consumed by whatever organic material remains and isn't replenished. Circulation stops entirely, so even if chemistry were present it wouldn't reach the shaded corners, steps, and dead spots where algae establishes first. And the pool sits that way for five or six months.

Algae doesn't need much to work with. It doesn't require warm water — cold-water species establish readily — and it doesn't need direct sun, particularly under a mesh cover that lets light through. What it needs is time without opposition, and a closed pool provides exactly that.

A winterizing algaecide is what fills the gap. It establishes a protective residual at closing that persists through the dormant months, suppressing growth in water that has no other defense. That's a genuinely different demand than a summer algaecide faces: no weekly top-up, no chlorine backing it up, no circulation distributing it. One application, months of duty.

The sequence within the closing routine matters for a chemical reason. The winter shock goes first because it oxidizes the season's accumulated organic load — and because high free chlorine degrades many algaecide actives. Applying the algaecide into freshly shocked water means paying for product that gets destroyed before it can establish. That's why the directions call for 2 to 4 hours of circulation between the shock and this product.

One boundary worth stating: this is an algaecide, not a sanitizer. It prevents algae growth; it doesn't disinfect, and it doesn't replace the winter shock. Both steps are part of a complete closing.

Pro Tip: Give the winter shock its full 2 to 4 hours of circulation before you add this — the wait is chemistry, not caution. High free chlorine oxidizes algaecide actives, so dosing both together destroys a meaningful share of the algaecide before it can establish a residual. On a closing day when you're trying to get everything done, that's the step most likely to get compressed, and it's the one that costs you the protection you just paid for. Shock in the morning, let it circulate through lunch, then add the algae protector.

Dosage Reference

• Approximately 16 fl oz per 12,000 gallons — one quart treats about 24,000 gallons
• Confirm the rate printed on your bottle before dosing. Dealer listings vary on this figure, and the label is authoritative.

Prior to Application

1. Test your pool water and follow directions to properly balance your water for conditions in your area.
2. If metals testing indicates a need to use a stain and scale inhibitor, apply that product per its label directions.
3. Allow the pool to circulate at least 1 hour before adding other products.

Application

1. Add the appropriate amount of winter shock according to the label directions of that product.
2. Allow to circulate 2 to 4 hours.
3. Then pour Arctic Blue Algae Protector into the pool around the edges with the pool circulation system operating.
4. Circulate pool water for 1 hour.
5. Then clean the filter and pool walls at the water line.
6. In areas with severe freezing, drain pool equipment and plumbing lines, or use an antifreeze recommended for swimming pool plumbing and equipment.

Timing Your Closing

• Close when water temperature is consistently below about 60°F. A pool closed warm stays warm enough under the cover for algae to keep growing.
• In the Intermountain West that typically means late September into October, depending on elevation and the season.
• Waiting two extra weeks for the water to cool costs nothing. Closing early can cost the entire spring opening.

Mesh Covers and Uncovered Pools

Mesh covers let sunlight and debris through, so those pools accumulate organic load and lose protection faster than solid-covered pools do. If your pool has a mesh cover or no cover at all, plan on checking it partway through the winter rather than assuming the closing treatment carries all the way to spring — a mid-winter treatment may be needed.

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: Buy the whole closing set at once and measure your pool before you order. A closing has a fixed sequence with real timing — shock, wait 2 to 4 hours, algaecide, wait 1 hour, closing treatment — and discovering mid-afternoon that you're short a product means either an unfinished closing or a shocked, unprotected pool sitting while you make a trip. Work out your gallonage once and write it on a tag in the equipment shed. You'll use that number at closing, at opening, and every time you dose anything for the rest of the pool's life.

• Brand: BioGuard
• Product Type: Winterizing pool algaecide
• Form: Liquid
• Volume: 1 quart (32 fl oz)
• Manufacturer Part Number: 24287BIO
• Algae Types Prevented: All types of pool algae
• Approximate Coverage: One quart per approximately 24,000 gallons — confirm on the current label
• Staining: Non-staining
• Mixing: No mixing or pre-dissolving needed
• Application Method: Pour around the edges of the pool with the circulation system operating
• Circulation After Application: 1 hour
• Required Wait After Winter Shock: 2–4 hours of circulation
• Sequence Position: Step 2 — after winter shock, before the closing treatment
• Recommended Closing Temperature: Water consistently below about 60°F
• Sanitizer Compatibility: Chlorinated and brominated pools
• Surface Compatibility: All pool surface types
• Filter Compatibility: All filter types
• Not A Substitute For: Winter shock, sanitizer, or water balancing
• Shipping Classification: DOT-regulated — ground shipping only

Pool Types and Surfaces

• In-ground and above-ground pools
• All surface types — plaster, gunite, vinyl liner, fiberglass, and painted
• All filter types — sand, cartridge, and DE

Sanitizer Programs

• Chlorinated pools — formulated for this application
• Brominated pools — formulated for this application
• Salt chlorine generator pools — compatible; a salt pool is a chlorine pool
• Biguanide pools — verify before use. Biguanide programs run their own closing chemistry, and the winter shock step in this sequence uses chlorine.

The Arctic Blue Closing Sequence

• Balance the water first — total alkalinity, then pH, then calcium hardness
• Step 1: Winter shock — oxidizes, clarifies, and buffers. Circulate 2–4 hours.
• Step 2: Algae Protector — this product. Circulate 1 hour.
• Step 3: Closing treatment — clarifies, prevents waterline buildup, removes phosphates.
• Then: clean the filter and waterline, lower the water level as your cover requires, winterize equipment and plumbing, and install the cover.

All three chemical steps are part of a complete closing. The shock alone does not winterize a pool.

Used With

• A winter shock, applied before this product
• A closing treatment, applied after
• A stain and scale inhibitor, if metals testing indicates one is needed
• Pool antifreeze for plumbing, in areas with severe freezing
• Winter covers of all types — solid, mesh, and safety

What It Does Not Do

• Not a sanitizer. Provides no disinfection and maintains no sanitizer residual.
• Not a shock or oxidizer. The winter shock is a separate required step.
• Not a substitute for water balance. Alkalinity, pH, and calcium hardness must be corrected before closing.
• Not a summer algaecide. This is formulated for off-season use in a closed pool.

Important Handling Cautions

• Never mix with other chemicals. Add each closing product separately with circulation between.
• Do not apply immediately after the winter shock. Allow 2–4 hours of circulation first.
• Test for metals before closing and apply a stain and scale inhibitor if needed.