Protein Skimmers are a quintessential part of the saltwater aquarium hobby. There are many skimmers to choose from, from many brands, all with different features and price points. My favorite skimmer is the Reef Octopus Classic INT series of skimmers. Here is a list of what makes them my favorite skimmer.

1. Price to Performance
The Reef Octopus Classic skimmers are not the absolute cheapest skimmers on the market, but they are reasonably priced for skimmers that perform so well. They use affordable AC pumps that are quiet enough that I have never gotten a customer complaint about the noise. They skim well enough that I see no reason to upgrade from an Octopus to another skimmer with more cool bells and whistles.

2. Three Sizes
The Octopus Classic INT skimmers come in three sizes. The Classic 110INT is perfect for 55, 60, 75, and 90-gallon tanks. The Classic 150INT is great for 110, 120, and 125-gallon tanks, and the Classic 200INT is excellent for 150, 180, and 210-gallon tanks.

3. External Pump
People hate maintaining their equipment so the easier it is to do the maintenance the better. The pump is the heart of a skimmer. It has the only moving part and the pump is the only thing that tends to wear out and break over time. With the Octopus INT skimmers, the pump is outside of the skimmer's body. This means that you can easily remove the pump by undoing one union. To clean, simply run the pump in a vinegar bath overnight. I believe that how well a skimmer is maintained is likely a bigger factor in the skimmer’s performance than how expensive the skimmer was when it was purchased.

Another added benefit is that as manufacturers update skimmers with new pumps and discontinue old pumps, skimmers with external pumps can easily have the new pump attached to the same union that the original pump was attached to. But if the pump was inside the skimmer, you will usually have to replace the entire skimmer once the pump goes out and the original replacement has been discontinued.

4. Gate Valve Outlet
There are a variety of water level controls for skimmers from gears, to wedge pipes, to gate valves. The gate valve is my personal favorite because it is far more robust and less likely to break than the complicated gear-based adjustments of many compact skimmers, and it has a lot more play for fine-tuning than a wedge pipe. A wedge pipe goes from completely closed to completely open in one-half turn of the pipe while a gate valve can usually take at least 2-3 complete turns to completely close and open. This means you have 4-6 times the amount of play than a wedge pipe does, which makes making fine adjustments much easier.

5. Only One Adjustment
Some new skimmers tout the fact that they have a pump speed adjustment, a water level adjustment, and an air intake adjustment. I find that this many adjustments confuse 90% of aquarists. They are unnecessary. When I have used most skimmers with all of these adjustments, I normally run the air wide open, the pump at full speed, and only use the water level adjustment anyway. The Octopus Classic Skimmers with the water level adjustment takes the keep-it-simple principle to heart.