Blue Diamond Pumps ET40 Septic & Pond Linear Diaphragm Air Pump — Weatherproof, Oil-Free, Quiet 1.41 CFM

Blue Diamond Pumps Blue Diamond ET 40 is a weatherproof linear diaphragm air pump that delivers clean, oil-free oxygen to ponds or septic systems year-round.

Designed for continuous aeration in water gardens, koi ponds, and small wastewater systems, the ET40 raises dissolved oxygen to clarify water and support healthy aquatic life. It runs quietly, uses modest power, and is built with replaceable parts so you can maintain performance over many seasons. The unit ships with a bronze 3/8" ID fitting and a connector sized to fit standard tubing; contact support for runs longer than 33 feet.

How does the ET40 improve pond water quality?

The ET40 forces a steady stream of clean air through diffuser lines to boost oxygen levels, encouraging beneficial bacteria and helping organic particles break down more effectively. Higher oxygen supports fish and plants while reducing cloudy water and foul odors.

• Max air output: 1.41 cubic feet per minute for continuous aeration
• Oil-free air delivery preserves water clarity and aquatic health
• Helps reduce anaerobic zones that cause odors and sludge

Can this pump prevent ice formation and work in cold climates?

Yes — the ET40 is weatherproof and suited for year-round operation, including winter use as a deicer to keep a small area of open water for gas exchange. Its robust construction resists cold exposure, making it a practical choice for ponds in temperate and colder regions.

• Weatherproof housing for outdoor placement
• Continuous operation capability to keep a ventilation hole in ice
• Sturdy materials formulated for the linear diaphragm extend winter durability

What are the noise, power, and service expectations?

The ET40 is engineered to run quietly, often comparable to background household noise, while consuming just 30 watts of electricity. Routine maintenance is straightforward: diaphragms are replaceable to restore performance without replacing the whole unit.

• Typical sound level as low as 35 decibels for low-disturbance operation
• 30 watts energy draw keeps operating costs modest
• Replaceable diaphragm kits (sold separately) simplify repairs and extend life

How easy is installation and what are the physical specs?

Setup is simple — the pump arrives with a bronze 3/8" ID fitting and a 0.55" OD connector that fits standard tubing. The compact footprint makes it easy to mount near a pond edge or septic basin, and the unit is serviceable so routine checks keep it dependable.

• Dimensions: 8.66" long x 6.10" wide x 7.48" tall for small-space placement
• Weight: 9.48 pounds for a stable installation
• Maximum pressure: 0.15 bar, suitable for short to moderate tubing lengths

Who is this for: The Blue Diamond Pumps ET40 suits pond owners, koi hobbyists, and homeowners managing small septic aeration needs who want reliable, low-noise oxygenation year-round. It’s ideal for users who value easy maintenance, weatherproof construction, and clean, oil-free air delivery. If you need longer tubing runs or higher pressure, contact the seller for guidance or consider models with greater capacity. Backed by a two-year manufacturer warranty, this pump balances steady performance and serviceability for hobby and light commercial water aeration tasks.