If you've ever noticed a greasy, oily film on the surface of your aquarium water, you've seen exactly why surface skimmers exist. That film — made up of proteins, oils, and organic waste — blocks gas exchange between the water and the air, which is one of the most important processes in a healthy planted tank. A surface skimmer solves this problem elegantly and continuously.
What Is a Surface Skimmer?
A surface skimmer is an inflow device that draws water from the very top of the water column — right at the surface — rather than from mid-water or the substrate. It's typically connected to the intake of your canister filter, replacing or supplementing the standard inflow strainer.
The 19mm in/out stainless steel pipe set with surface skimmer integrated
As the skimmer draws water in, it pulls the surface film along with it, sending it through the filter media where it's broken down and removed. The result is a crystal-clear, ripple-free water surface that looks stunning and functions better.
Why the Water Surface Matters in a Planted Tank
In a planted aquarium, gas exchange at the water surface is critical for two reasons:
- Oxygen — plants and fish both need dissolved oxygen. A clean surface allows O2 to enter the water freely. Beneficial bacteria in the tank also got the benefits from the oxygen rich in the water column.
- CO2 retention — if you're injecting CO2, you want to minimise surface agitation to keep dissolved CO2 in the water where plants can use it. A surface skimmer achieves this by drawing water in gently, without creating turbulence.
A surface film blocks both of these processes. Even a thin protein film can significantly reduce gas exchange efficiency, leading to stressed fish, slower plant growth, and cloudier water.
Signs You Need a Surface Skimmer
- Visible oily or foamy film on the water surface
- Dull, hazy water despite good filtration
- Fish gasping at the surface (a sign of low dissolved oxygen)
- Slower than expected plant growth despite good lighting and CO2
- Unpleasant smell from the tank
Surface Skimmers and Stainless Steel Inflow Pipes
Many aquascapers use a surface skimmer on the inflow side and a stainless steel jet pipe on the outflow side — this is the most effective combination for planted tanks. The jet pipe creates a directed current that circulates water and CO2 across the substrate, while the skimmer keeps the surface clean and gas exchange unobstructed.
A set of 9mm in/out stainless steel pipe set with surface skimmer integrated
LitiAquaria stainless steel jet pipes are available in sizes to match your canister filter:
- 9mm Jet Pipes — for nano filters (OASE FiltoSmart 60, Eheim 2211)
- 12mm Jet Pipes — for mid-range filters (Eheim 2213/2215, OASE FiltoSmart100, Eheim Ecco Pro)
- 16mm Jet Pipes — for larger filters (Eheim Professional 3, OASE BioMaster, OASE FiltoSmart 200/300)
- 19mm Jet Pipes — for high-flow filters (Aquael Ultramax 2000, Aquael Hypermax 4500)
How to Position a Surface Skimmer
For best results, position the skimmer so the intake slot sits right at the waterline — half in, half out of the water. The acrylic surface skimmer part level would be floating according to the water level.
Theoretically, the surface skimmer works when there is enough pulling force from the filter flow. The filter needs to have a sufficient flow rate to overcome the buoyancy of the plastic skimmer part.
To adjust the pulling force, you can try the following:
- Swivel the bottom part of the inlet pipe to throttle the flow coming from the bottom, which increases the inflow from the top and boosts the pulling force of the plastic surface skimmer. Make sure the filter is clean to maintain good flow.
-
Reduce the buoyancy of the float by adding a small amount of water to the plastic skimmer's void portion (using an injection syringe 😊).
Place the skimmer on the side by side to your outflow jet pipe. This creates a full circulation loop: water flows out from the jet pipe, travels across the tank, and returns via the skimmer — maximising both CO2 distribution and surface cleaning.
Maintenance
The acrylic surface skimmer part need regular cleaning — typically every 1–2 weeks depending on your bioload. The intake slots can clog with algae or debris, reducing flow. A quick brush and rinse under tap water during your regular water change is usually sufficient.
The Bottom Line
A surface skimmer is one of the most cost-effective upgrades you can make to a planted tank. It improves water quality, supports CO2 efficiency, and keeps your aquascape looking its best. Paired with quality stainless steel outflow pipes, it's the foundation of a well-circulated, healthy planted aquarium.