Choosing a floating cover is one of the most consequential decisions an operator can make for a pond, lagoon, reservoir, or digester. The right cover reduces evaporation, controls odor, retains heat, and pays for itself — often within 12 to 24 months. The wrong cover creates maintenance headaches, fails in storms, and wastes capital.
At AWTT, we invented the self-ballasting hexagonal floating cover and have deployed more than 700 installations across six continents. We manufacture four distinct modular product lines, and we have installed them alongside — and as replacements for — traditional geomembranes. That gives us a perspective few others can offer: direct, field-validated comparison data across every major floating cover type on the market.
This guide compares all five categories head-to-head, with real specifications, honest pros and cons, and clear guidance on which type fits which application.
At a Glance: Floating Cover Comparison Table
| Specification | Ball Covers (Armor Ball) | Hexagonal Tiles (Hexprotect AQUA) | Hybrid Panels (Rhombo Hexoshield 66) | Insulated Covers (Hexprotect MAX R) | Traditional Geomembranes |
|---|---|---|---|---|---|
| Surface Coverage | 91% | 99% | 99% | 99% | 100% (when intact) |
| Wind Resistance | 35 MPH (standard) / 75 MPH (AQUA) | 130+ MPH (water-ballasted) | 130 MPH (water-ballasted) | 40 MPH | Varies; requires full perimeter anchoring |
| R-Value | R-2 | R-2 | R-4 (66) / R-8 (189) | R-17+ | R-0 (single sheet) |
| Evaporation Reduction | 80–85% | 95–99% | 93–98% | 95–99% | 95–100% (when intact) |
| Buoyancy | Standard | Standard | 25 lb/ft² (66) / 50 lb/ft² (189) | Standard | N/A (sheet floats on surface) |
| Installation | Pour from edge or boat | Pour from edge or boat | Pour from edge or boat | Pour from edge or boat | Custom fabrication, heavy equipment, divers |
| Scalability | Any size / shape | Any size / shape | Any size / shape | Any size / shape | Custom-cut per project |
| Maintenance | Minimal | Minimal | Minimal | Minimal | Pumps, inspections, repairs, reseaming |
| NSF Food-Grade Option | No | Yes | No | No | Varies |
| Typical Lifespan | 15–25+ years | 15–25+ years | 15–25+ years | 15–25+ years | 10–20 years (with maintenance) |
| Best Application | Sheltered ponds, budget projects | General-purpose, high-wind, potable water | Heat retention, heavy-load environments | Biogas digesters, heated processes | Full containment, gas collection |
1. Ball Covers (Armor Ball)
How It Works
Armor Ball covers consist of individual hollow HDPE spheres that float freely on the water surface. Each ball is approximately 100 mm in diameter. When deployed in bulk, the balls self-arrange into a dense floating blanket driven by surface tension and gravity. No fastening, tethering, or mechanical connection is required — you simply pour them onto the water surface from the bank or from a boat.
The standard Armor Ball is air-filled and designed for sheltered environments. The Armor Ball AQUA variant adds a water-ballast chamber that significantly increases its effective weight on the surface, raising wind resistance from 35 MPH to 75 MPH.
Key Specifications
- Surface coverage: 91% (geometry of spheres prevents full tessellation)
- Wind resistance: 35 MPH (standard) / 75 MPH (AQUA variant with water ballast)
- R-value: R-2
- Evaporation reduction: 80–85%
- Material: UV-stabilized HDPE
- Installation: Bulk pour, no tools or heavy equipment
Best Applications
Ball covers excel in sheltered ponds, indoor tanks, small to mid-size lagoons, and any application where budget is the primary constraint. They are widely used for frac ponds, mining process water, cooling ponds, and chemical storage tanks where moderate evaporation reduction is sufficient and wind exposure is limited.
Pros
- Lowest cost per square foot of any modular floating cover
- Fastest installation — literally pour and walk away
- Individually replaceable; damage to one ball does not affect the system
- No mechanical connections, anchoring, or perimeter hardware
- Works on irregular shapes, around obstructions, and on changing water levels
- AQUA variant extends wind resistance to 75 MPH for moderate-exposure sites
Cons
- 91% coverage leaves 9% of the surface exposed, limiting maximum evaporation control
- Standard version limited to 35 MPH wind — not suitable for open, high-wind sites
- Lower R-value (R-2) compared to hybrid and insulated options
- Spherical geometry means some light and air exchange at interstitial gaps
- Not available in NSF food-grade formulation
For full specifications, see the Armor Ball product page and Armor Ball AQUA product page.
2. Hexagonal Tile Covers (Hexprotect AQUA)
How It Works
Hexprotect AQUA is the product that started modular floating cover technology. Each unit is a hexagonal tile — a flat-topped, hollow HDPE module that tessellates with its neighbors to form a near-continuous floating mat. The hexagonal geometry is critical: unlike spheres, hexagons achieve 99% surface coverage with minimal interstitial gaps.
Each tile incorporates a water-ballast chamber. When deployed, water enters the chamber through a calibrated port, adding mass that locks the tile against the surface. This self-ballasting mechanism is what makes Hexprotect AQUA capable of withstanding winds exceeding 130 MPH — a claim validated by surviving four named hurricanes, including direct hits from Category 4 storms.
Key Specifications
- Surface coverage: 99%
- Wind resistance: 130+ MPH (self-ballasting, water-filled)
- R-value: R-2
- Evaporation reduction: 95–99%
- Material: UV-stabilized HDPE; NSF/ANSI 61 food-grade option available
- Installation: Bulk pour from edge or boat; self-arranging on water surface
Best Applications
Hexprotect AQUA is the most versatile product in the modular floating cover category. It is the default choice for municipal potable water reservoirs (NSF-certified), wastewater lagoons, industrial process ponds, mining tailings, and any site where high evaporation reduction and hurricane-grade wind resistance are required. Its 99% coverage also makes it effective for odor control and algae suppression.
Pros
- 99% surface coverage — the highest of any modular system
- 130+ MPH wind resistance, field-proven through four hurricanes
- NSF/ANSI 61 certified option for potable water and food-grade contact
- Self-ballasting with no mechanical anchoring required
- Works on any shape, any size, with fluctuating water levels
- Suppresses algae growth by blocking UV light penetration
- Individually replaceable modules; no system-wide failure modes
- 15–25+ year expected lifespan with zero scheduled maintenance
Cons
- R-2 insulation value — adequate for evaporation and algae control but not optimized for heat retention applications
- Higher cost per square foot than ball covers (offset by superior performance)
- For applications requiring R-4 or higher, hybrid or insulated covers are more appropriate
For full specifications, see the Hexprotect AQUA product page and technical data sheets.
3. Hybrid Panel Covers (Rhombo Hexoshield 66 / 189)
How It Works
The Rhombo Hexoshield line represents the next evolution in modular floating covers, combining the tessellation advantages of hexagonal geometry with integrated foam insulation and reinforced structural panels. Each module is larger than a standard Hexprotect tile and incorporates closed-cell insulating foam within a rigid HDPE shell.
The Rhombo Hexoshield 66 delivers R-4 insulation and 25 lb/ft² of buoyancy, with water-ballasted wind resistance up to 130 MPH. It won a U.S. Department of Energy award for innovation in water-energy nexus technology.
The Rhombo Hexoshield 189 is the heavy-duty variant, doubling the insulation to R-8 and buoyancy to 50 lb/ft² while maintaining 90+ MPH wind resistance. The 189 is designed for environments where panels may need to support snow loads, ice formation, equipment, or walkway systems.
Key Specifications
Rhombo Hexoshield 66:
- Surface coverage: 99%
- Wind resistance: 130 MPH (water-ballasted)
- R-value: R-4
- Buoyancy: 25 lb/ft²
- Evaporation reduction: 93–98%
Rhombo Hexoshield 189:
- Surface coverage: 99%
- Wind resistance: 90+ MPH
- R-value: R-8
- Buoyancy: 50 lb/ft²
- Evaporation reduction: 93–98%
Best Applications
Hybrid panels are the optimal choice when both thermal insulation and wind resistance are required. Typical applications include heated process ponds, aeration basins, industrial lagoons in cold climates, and any site where heat loss through the water surface represents a significant operational cost. The DOE award specifically recognized the Rhombo Hexoshield 66’s ability to reduce energy consumption at water treatment facilities.
The Rhombo 189 is particularly suited to northern climates where snow and ice loading are design considerations, as well as applications where the cover must support monitoring equipment or temporary foot traffic.
Pros
- R-4 to R-8 insulation — 2x to 4x the thermal performance of standard hexagonal tiles
- 130 MPH wind resistance (66 model) proven in field conditions
- DOE award-winning technology validated by independent testing
- 25–50 lb/ft² buoyancy supports snow loads, ice, and light equipment
- Modular installation identical to other AWTT products — pour from edge or boat
- 99% surface coverage with effective evaporation and odor control
- No anchoring, pumps, or perimeter hardware required
Cons
- Higher cost per square foot than ball covers or standard hexagonal tiles
- 99% coverage vs. 99% for Hexprotect AQUA (marginal difference in most applications)
- Larger individual module size may require slightly more coordination during deployment
- Not available with NSF food-grade certification
For full specifications, see the Rhombo Hexoshield product page and Rhombo 189 product page.
4. Insulated Covers (Hexprotect MAX R)
How It Works
Hexprotect MAX R is purpose-built for applications where thermal performance is the dominant requirement. Each module uses the same hexagonal tessellation geometry as the Hexprotect AQUA but incorporates a thick closed-cell foam core that delivers R-17 or higher insulation — the highest thermal resistance of any floating cover on the market.
The design philosophy is different from the hybrid panels: where Rhombo Hexoshield balances wind resistance, buoyancy, and insulation, the MAX R prioritizes maximum heat retention above all else. It is rated for 40 MPH wind, which is appropriate for its primary application in biogas digesters and enclosed or semi-enclosed heated tanks where extreme wind exposure is uncommon.
Despite the 40 MPH standard wind rating, Hexprotect MAX R installations have survived hurricane conditions, demonstrating the inherent resilience of the modular self-ballasting design even at lower wind ratings.
Key Specifications
- Surface coverage: 99%
- Wind resistance: 40 MPH
- R-value: R-17+
- Evaporation reduction: 95–99%
- Heating cost reduction: Up to 85%
- Material: UV-stabilized HDPE shell with closed-cell foam core
Best Applications
Hexprotect MAX R is the definitive choice for biogas digesters, anaerobic lagoons, heated process tanks, and any application where maintaining water temperature directly affects process efficiency or energy costs. Biogas production rates are highly temperature-dependent — a 5 degree F drop in digester temperature can reduce methane output by 10–15%. At R-17+, the MAX R effectively eliminates radiant and convective heat loss through the water surface.
Operators of heated industrial processes — food and beverage, pulp and paper, pharmaceutical, and chemical manufacturing — routinely report heating cost reductions of 70–85% after MAX R installation.
Pros
- R-17+ insulation — the highest of any floating cover system, by a wide margin
- 99% surface coverage matching Hexprotect AQUA
- Up to 85% reduction in heating energy costs, with typical payback under 12 months
- Dramatically improves biogas yield by stabilizing digester temperature
- Same modular, no-anchor, pour-and-deploy installation as all AWTT products
- Hurricane-survivable despite 40 MPH rating, proven in field conditions
- 15–25+ year lifespan with no scheduled maintenance
Cons
- 40 MPH wind rating limits suitability for exposed, high-wind sites
- Higher cost per square foot than standard hexagonal tiles (justified by energy savings)
- Foam core adds buoyancy but modules are slightly thicker, increasing shipping volume
- Not designed for heavy snow or ice loads — hybrid panels are better for that application
- Not available with NSF food-grade certification
For full specifications, see the Hexprotect MAX R product page and technical data sheets.
5. Traditional Geomembranes
How It Works
Geomembrane floating covers are large sheets of synthetic material — typically HDPE, LLDPE, or reinforced polypropylene — custom-fabricated to fit the exact dimensions of a pond or lagoon. The sheet is floated on the water surface and anchored around the full perimeter using trenches, batten strips, or mechanical fasteners. Rainwater collection systems (pumps, sumps, and drainage channels) are installed on top of the membrane to prevent ponding and potential sinking.
Geomembranes have been used for decades and remain common in applications requiring full gas containment, such as landfill leachate ponds and certain biogas collection systems where captured gas must be channeled to a flare or generator.
Key Specifications
- Surface coverage: 100% (when intact and properly maintained)
- Wind resistance: Dependent on anchoring system; can fail catastrophically in high winds if gas accumulates beneath the membrane
- R-value: R-0 (single-layer sheet provides negligible insulation)
- Evaporation reduction: 95–100% (when intact)
- Material: HDPE, LLDPE, or reinforced polypropylene
- Installation: Custom fabrication, heavy equipment, field seaming, perimeter anchoring
Best Applications
Geomembranes remain the appropriate choice when full gas containment is the primary requirement — specifically, when captured biogas or landfill gas must be collected under pressure and routed to utilization or flare equipment. They are also used in regulatory environments that specifically mandate continuous-sheet covers.
Pros
- 100% surface coverage and gas containment when properly installed and maintained
- Decades of regulatory acceptance and engineering precedent
- Can be integrated with gas collection piping for biogas or landfill gas capture
- Available in a range of thicknesses and materials for chemical compatibility
Cons
- High installation cost: Requires custom fabrication, field seaming by certified welders, heavy equipment for deployment, and full perimeter anchoring systems. Typical installed costs are 30–50% higher than modular alternatives for equivalent surface areas.
- Ongoing maintenance burden: Rainwater pumps must run continuously or after every storm event. Pump failure leads to ponding, membrane sag, and potential catastrophic failure. Regular inspections are required to detect seam failures, tears, and UV degradation.
- Vulnerability to wind and gas uplift: Geomembranes can balloon and tear when gas accumulates beneath the sheet or when wind gets under an edge. Unlike modular systems, a single failure point can compromise the entire cover.
- No insulation: A single sheet of HDPE or LLDPE provides effectively R-0 thermal resistance. Insulated geomembranes exist but add significant cost and complexity.
- Difficult to adapt: Any change in pond geometry, water level range, or operational requirements may require partial or complete replacement. Modular systems simply add or remove units.
- Rigid infrastructure: Perimeter anchoring, access hatches, and drainage systems are permanent installations that complicate pond maintenance, dredging, and equipment access.
- Shorter effective lifespan: While material ratings suggest 20+ years, field experience shows that seam degradation, UV damage, and mechanical wear typically necessitate major repairs or replacement within 10–15 years.
Cost Comparison: Total Cost of Ownership
Initial purchase price is only part of the equation. The true comparison requires accounting for installation labor, equipment, maintenance, and operational costs over the system’s lifespan.
| Cost Factor | Modular Covers (Ball, Hex, Hybrid, Insulated) | Traditional Geomembranes |
|---|---|---|
| Material cost | Moderate (varies by product) | Moderate to high |
| Installation labor | Low — no specialized skills, no heavy equipment | High — certified welders, heavy equipment, multi-day install |
| Perimeter anchoring | None required | Full perimeter system required |
| Rainwater management | Self-draining (water passes between modules) | Pumps, sumps, and drainage required |
| Ongoing maintenance | Near-zero (replace individual units as needed) | Pump operation, inspection, seam repair, debris removal |
| Adaptability cost | Add or remove units at will | Partial or full replacement for changes |
| 10-year total cost | Typically 30–50% lower than geomembranes | Higher due to maintenance, pump energy, and repair costs |
For a detailed cost estimate tailored to your specific site, use our project calculators or contact our engineering team directly.
How to Choose the Right Floating Cover
Selecting the optimal cover type depends on four primary factors: your site’s wind exposure, your thermal requirements, your coverage needs, and your budget constraints. Here is a simplified decision framework:
Start with wind exposure:
- Sheltered site (under 35 MPH): All five types are viable. Ball covers offer the lowest cost.
- Moderate exposure (35–75 MPH): Armor Ball AQUA, Hexprotect AQUA, Rhombo Hexoshield, or geomembranes.
- High exposure or hurricane zone (75–130+ MPH): Hexprotect AQUA or Rhombo Hexoshield 66. These are the only floating covers field-proven above 100 MPH.
Then evaluate thermal needs:
- No insulation required (evaporation/odor control only): Hexprotect AQUA or Armor Ball.
- Moderate insulation (R-2 to R-8): Rhombo Hexoshield 66 (R-4) or Rhombo Hexoshield 189 (R-8).
- Maximum insulation (R-17+): Hexprotect MAX R. Nothing else comes close for heated processes and biogas digesters.
Consider coverage requirements:
- 80–85% evaporation reduction acceptable: Armor Ball at 91% coverage.
- 95%+ evaporation reduction required: Hexprotect AQUA (99%), Rhombo Hexoshield (98%), or Hexprotect MAX R (99%).
- Full gas containment required: Traditional geomembrane is the only option for pressurized gas collection.
Factor in total cost of ownership:
- Lowest upfront cost: Armor Ball.
- Lowest 10-year total cost for most applications: Hexprotect AQUA or Rhombo Hexoshield.
- Fastest ROI for heated applications: Hexprotect MAX R, with typical payback under 12 months.
For a guided recommendation based on your specific site conditions, industry, and operational requirements, use our Product Selector Tool. It takes less than two minutes and delivers a tailored recommendation with preliminary sizing.
Why AWTT
AWTT is not a reseller or distributor. We are the original inventor and manufacturer of self-ballasting hexagonal floating covers. Every product in our modular line — from the Armor Ball to the Hexprotect MAX R — is designed, engineered, and manufactured under our direct quality control.
With more than 700 installations worldwide, we have field performance data spanning every climate zone, every major industry, and every scale from 500-square-foot tanks to 50-acre reservoirs. That data is what allows us to publish the specific numbers in this guide with confidence.
If you are evaluating floating covers for a current or upcoming project, we encourage you to:
- Explore our full product line and technical data sheets
- Run preliminary numbers with our project calculators
- Use the Product Selector for a tailored recommendation
- Contact our engineering team for a no-obligation consultation and site-specific proposal
The right floating cover pays for itself. Let us help you find it.