Buyer's guide to external filters


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Thinking of getting an external filter? Want to know which ones to buy? Jeremy Gay explains what he expects of them and makes his recommendations.

When I select an external filter for one of my tanks I’m clear what I want from it. It needs to come with everything I need, including filter media, and give me the pipework options to fit a wide range of different tank models.

It should be straightforward to put together and should prime (fill with water and be ready to run) using a button within seconds.

It should be quiet, shouldn’t leak of course, and be reliable. After all, these outlays aren’t cheap…

I don’t like too much specialised media design. I want to be able to fill my external with my choice of media — and I like the pump inside the head unit on the filter, not in the tank, so I can choose my pipework inlets and outlets.

External filters are much better than they used to be and there aren’t many I wouldn’t touch. Comparing them can be interesting though, as some are manufactured in China and can be pretty similar although under different branding.

Clever filters are all the rage, including those with microchips controlling the pump, although from the models I’ve tested I find too much computer-tech can be a turn-off when it doesn’t need it.

I recommend:

Anything Fluval…

Be it an '06, a G series or an FX5, you simply cannot go wrong with Fluval. I even cut my external filtering teeth on the '04 and '05s!

They’re easy to prime, quiet, reliable, come with all the media and are dead easy to get going and service. I’d recommend these time and time again and sleep well knowing that I had done.

The G series literally broke the mould in aquarium filtration and in many ways is the world’s best external filter. The LED screen monitors water conductivity as well as overviews continuous performance, but what does it for me is the ease of maintaining the mechanical and chemical filtration chambers. I find this an absolute joy and the biggest innovation in filter technology since the Prime was mastered.

I’d describe the FX5 as the 4x4 of external filters, being all terrain, having the most grunt, most torque and being able to handle more muck than any other external filter. Yet when you get that sizeable intake strainer out of the box and those 2.5cm/1” pipe fittings you realise you are dealing more with a monster truck than a 4x4 — and the big messy fish owners of this world simply love them.

Before the FX5, big fish owners used pond filtration in various DIY formations. Now they all just use FX5s... Enough said.

Almost anything Eheim…

I changed that wording at the last moment, altering my Eheim recommendation from 'anything Eheim' to 'almost anything Eheim'!

From the seemingly hundreds of models available (some on sale since 1981), I’m not a massive fan of the Aquacompact (unsightly pump in main tank,) Classic (no priming button,) Experience (no priming button) or surprisingly the all-singing-all dancing Professional 3e (too complicated.)

Instead give me an Ecco Pro or a standard Professional 3, or, better still, a Professional 3 thermofilter option, and I will surely feel in filtering heaven.

The Ecco is super efficient, easy to open, clean and load with media and good value for money. The Professional 3 is everything you want from an Eheim — being large, sturdy, reliable, well built and having huge media capacity — and if I was to choose just one to see out my fishkeeping days it would probably be one of these.

TetraTec from Tetra

Known more for its fish food than equipment these days, Tetra does make a very good external filter which ticks all the boxes.

It’s easy to prime, powerful, quiet, reliable, comes with the media and all the pipe fittings, and I’d happily use one and recommend it to any tropical or coldwater fishkeeper.

The largest model, the EX2400, is a bit noisy as it’s frankly huge, so if into the larger filter market go for the FX5 instead.

CristalProfi from JBL

JBL makes some excellent external filters with thoughtful designs, excellent media options and interesting add-on bits like a surface skimmer.

Again they tick all my boxes, including having media, being easy to use, set up and prime, and being quiet and reliable.

The company has even reduced already low energy consumption of existing models and introduced even more efficient '01' models.

V2 PowerBox from TMC

TMC is the new kid on the external filter block and although I feared the unknown before using it I was pleasantly surprised. It looks good, feels quality and has a great big prime button. It has nice media options too.

Aquis Pro from AquaOne

I like the Aquis Pro as it combines everything I want. I don’t like the non-Pro Aquis anywhere near as much, as you have to prime it with a jug, and I don’t like the Aquis Pro 2450UV-C as I find externals with built-in UVs a faff.

However, stick to the Aquis Pro 550-1250 models and you’ll be a contented fishkeeper.

If you can afford it…

If you’ve a spare grand for larger models, get yourself an ADA Super Jet filter. There’s no prime button and no shut-off taps, but the Super Jet is a beauty, a design classic, and because of its looks and materials I will one day get one. Then all other thoughts of practicality or strategic buying patterns will go straight out of the window!

This isn’t a filter to hide in the cabinet. It has to be in full view, complementing your home. It’s a statement to be made.

What’s more, you don’t want one, you need two: the other to leave in mint condition for decades until ADA stops making them and then it could be worth thousands!

Pipped at the post…

….is the Nexx external filter from Mars Fishcare. Many love this, even voting it freshwater product of the year in PFK’s most recent reader’s poll, but that pump in the main tank puts me off.

I know why they’ve done it — meaning instant prime — and it has many other useful features like ease of filter maintenance, but the jury is out...

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