As one of the leaders of the filter manufacturing industry, Fluval is turning out state of the art filters that set market standards. And now from them comes a another superb underwater filter, the Fluval U4 Filter. Like other Fluval systems, this one is powerful enough to take on large aquariums, and even tanks for turtles and other large life forms. Do you have a terrarium you need filtered – well then, the Fluval U4 might just be the filter for you.

Lets take a closer look at this useful device. Firstly this filter allows you to create cleansing water motion with the help of a tri-setting control rod. There is a swivel mechanism in the output spout that allows you to alter the flow in a ninety degree rotational angle. All these little features will together enable you to create cleansing currents in the aquarium that will not only look aesthetic (think of the plants gently waving in the underwater currents) but just as importantly, will ensure that all the water in the tank eventually moves through the filter. The filter itself is powerful enough to handle fairly large tanks.

The filtration media is elementary to change – the filter's top simply flips open, and you take out the old cartridges and insert new ones. What could be simpler? The cartridges themselves have double filters so that you can replace them alternately. And if your tank needs even more heavy duty filtration, the Fluval U4 can handle it – it is very versatile and comes with additional areas in which you can easily insert mechanical filtration cartridges, such as pads of carbon fiber, for example.

Of course you'll need to change these pads at different intervals, but that shouldn't be a problem at all. In general terms, if you use foam pads as a filtration media, you'd have to change them every three to six months or so, but if you use a biological filtration system, you just need to change the filter twice a year.Beware of clogging though! The time periods I've specified are just general, and may not suit your tank. But there's no need to worry – the filter comes with a built in indicator that will tell you when the filtration media needs to be changed. This filter is excellent for smaller tank up to fifty seven gallons.

Pros and Cons

Good points:

• A powerful yet compact filter for the medium sized tank.
• Easily changeable media.
• A 90 degree swivel makes it easy to control the water flow inside the tank.

Bad points:

• Insufficient capacity for the larger tanks.
• Prone to clogging if with certain kinds of filtration media.
• If it's swivel is not set correctly, it can disturb the different elements and the arrangements within the tank

Manufacturer Specs

Fluval U4 Underwater Filter Bring powerful 3-stage filtration and circulation to hard-to-filter places like aquariums, terrariums and turtle tanks with the Fluval U Series Underwater Filter. This completely submersible filter features a unique 3-way flow control spray bar that allows you to create water movement anywhere you need it. Efficient Fluval design uses a handy flip-top to make media changing simple and fast.