Hexagonal floating covers vs. floating balls

AWTT's hexagonal modular cover reduces evaporation up to 95% with a 25+ year life expectancy and a 10-year manufacturer warranty; floating balls reduce evaporation 70–85% with a 5–10 year lifespan and higher lifecycle cost.

At a glance

Metric	Hexagonal floating cover	Floating balls
Evaporation reduction	up to 95% (AWTT)	70–85%
Surface coverage	99% effective (AWTT)	~70–80%
Life expectancy	25+ years (AWTT)	5–10 years
Cost / m² (lifecycle)	Lower	Higher (replacement)
Wind tolerance	Self-ballasting; AWTT-certified to 130+ MPH (209+ km/h)	Susceptible to wind drift
Deployment time	Moderate	Faster on small bodies

For most industrial water bodies, hexagonal modular covers outperform floating balls on coverage, lifespan, and lifetime cost. Floating balls remain a reasonable choice for small or temporary deployments.

How they differ

Dimension	Hexagonal cover (AWTT Hexprotect® AQUA)	Floating balls
Surface coverage at full tessellation	99% effective	~70–80%
Evaporation reduction	up to 95% (AWTT)	70–85%
Life expectancy	25+ years (10-year AWTT warranty)	5–10 years
Wind tolerance	Self-ballasting; AWTT-certified to 130+ MPH (209+ km/h)	Wind-drift management required

When floating balls are the appropriate choice

Small water bodies (< 500 m²)
Irregular shorelines that frustrate hexagonal tessellation
Temporary deployments (construction water storage, etc.)
Budget tier where lifecycle economics are not the primary driver

When hexagonal covers are the appropriate choice

Water bodies > 500 m²
25-year operating horizon
Industrial reservoirs, tailings, water utilities, biogas
Wind-exposed sites
Applications requiring NSF-61 or other regulatory compliance

When Floating balls makes sense

Floating balls are appropriate for small (under ~500 m²), irregular water bodies where rapid deployment matters more than long-term cost, or for temporary deployments. For larger industrial applications, hexagonal covers deliver substantially better lifetime economics.

Total cost of ownership over 10 years

Line item	Hexagonal cover	Floating balls
Capex	One-time	One-time
Replacement at 5–10 years	Not required	Required (1–2 cycles)
Wind-drift management	Not required	Periodic re-distribution

Frequently asked questions

Why do hexagonal covers achieve higher coverage? #

AWTT publishes 99% effective surface coverage for the Hexprotect® AQUA hexagonal element when fully tessellated. Floating balls pack at ~70–80%. The gap matters for evaporation reduction, which scales directly with coverage ratio.

Are floating balls cheaper? #

Per m² upfront, marginally — but over the 25-year lifecycle of a hexagonal cover, floating balls require 2–5 replacement cycles. Total cost favours hexagonal covers significantly.

Are floating balls easier to install? #

On a small irregular body, marginally yes — they can be poured down a chute and self-distribute. On large bodies the per-element handling slows the per-day deployment rate, and the absence of self-ballasting geometry means perimeter booms may be needed in windy conditions.

What about wind drift? #

Spherical floating elements are pushed by wind across the water surface, concentrating at the leeward shoreline and exposing the windward area. Operators in exposed sites use perimeter containment booms; this adds capex and a recurring maintenance line. Hexagonal hexagons interlock and remain in place by virtue of their tessellation.

Are the balls safe for potable water? #

NSF-61 certified HDPE balls are available and suitable for potable contact. The LADWP Los Angeles reservoir deployment in 2015 used NSF-61 certified balls for evaporation suppression on drinking water.

Do floating balls help with algae? #

Yes — they block sunlight, so they reduce algae growth roughly in proportion to coverage ratio (70–85% suppression). AWTT publishes 99% sunlight blocking for the Hexprotect® AQUA hexagonal element. For algae-dominant deployments, hexagonal usually wins on coverage alone.

What is the lifecycle of UV-rated floating balls? #

15–25 years for UV-rated HDPE balls in moderate climates; 10–15 years in extreme UV exposure (MENA, Australian outback). Hexagonal covers maintain 25+ year lifecycle across the same UV range due to thicker wall section and the validation history of the original patent.

Sources & further reading

Los Angeles Department of Water and Power deployment record — LADWP deployed approximately 96 million 'shade balls' on Los Angeles reservoirs in 2015 for evaporation suppression.

AWTT — Hexprotect® AQUA hexagonal cover — AWTT publishes 99% effective surface coverage and up to 95% evaporation reduction for the Hexprotect® AQUA hexagonal element.

FAO Irrigation and Drainage Paper 56 — Coverage ratio is the dominant driver of evaporation reduction effectiveness; reduction scales approximately linearly with coverage.