Surface Skimmer

A surface skimmer is a device that continuously removes the protein film, floating debris, and oily residue that accumulates on the water surface of an aquarium. This biofilm blocks gas exchange between the water and air, reducing oxygen levels and trapping CO2. A clean water surface is essential for a healthy, clear aquarium.

Why Surface Skimming Matters

• Gas Exchange: The water surface is where oxygen enters and CO2 escapes. A protein film acts as a barrier, suffocating your tank.
• Light Penetration: Surface film refracts and blocks light, reducing PAR reaching your plants.
• Aesthetics: A clear, mirror-like water surface dramatically improves the visual impact of your aquascape.
• Evaporation: A clean surface allows healthy evaporation rates.

Types of Surface Skimmers

Motorised Skimmer

A small, self-contained unit with an internal motor that draws surface water through a floating intake and passes it through a sponge or to the filter return.

• Examples: Eheim Skim 350, ADA VUPPA-I.
• Best for: Standalone surface cleaning in tanks without a sump.

Lily Pipe Surface Skimmer Intake

A modified glass or stainless steel intake pipe with a floating head that sits at the water line, drawing surface water directly into the canister filter.

• Examples: ADA Surface Skimmer, Cal Aqua Labs Siphon.
• Best for: Aquascapers who want to combine filtration intake with surface skimming.

Overflow Surface Skimmer

Used with sump setups. Water overflows from the display tank into the sump, inherently skimming the surface.

• Best for: Reef and large planted tank setups with sumps.

Installation Tips

• Positioning: Place the skimmer in an area with natural water flow to ensure surface debris is carried towards it.
• Water Level: Ensure the skimmer's intake sits exactly at the water line. Too high and it draws air; too low and it doesn't skim effectively.
• Flow Rate: Adjust to a gentle draw — too strong and it creates excessive surface disturbance.

Maintenance

• Clean the intake sponge or screen weekly to prevent clogging.
• Wipe any algae buildup from the floating head or intake assembly.
• Check that the float mechanism moves freely and adjusts to water level changes.

Trusted Brands

• Eheim: Skim 350 — reliable, quiet, and effective for tanks up to 350L.
• ADA: VUPPA-I — premium, beautiful design, pairs with ADA tanks.
• Cal Aqua Labs: Glass surface skimmer intakes.
• Oase: BioPlus Thermo internal filter with surface skim function.

Pros & Cons

Advantages

• Improved Gas Exchange: Dramatically boosts oxygen levels.
• Crystal Clarity: Removes surface haze for a clean look.
• Better Lighting: Removes the refractive film that blocks PAR.
• Low Maintenance: Simple cleaning.

Considerations

• Visibility: Motorised units are visible inside the tank.
• Noise: Some units produce a slight hum or trickling sound.
• Water Level Sensitivity: Must be positioned precisely at the waterline.