Written by Terry Smith

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Best Pond Filter Box Reviewed UK

This article was last updated on August 7th, 2021 at 3:43 am

A nice garden pond can really transform your backyard into something special if done right. To be honest, they’re not that hard to make yourself, as we’ve shown in our how to build a garden pond article, right here on this site. But building it is just the first step. You will need to make sure that the water is properly filtered or it could end up turning murky and not too pleasing to the old nostrils. If you are thinking of keeping fish in your pond, then you will definitely need a filtration system of some kind, and there are few different types available to you.

In this article we will review the best pond filter boxes out there, and offer up some helpful advice in our buyer’s guide, so you can feel confident you are making the right choice and get proper value for your money.

Best pond filter box reviews

Here are our reviews of the best pond filter boxes out there. We’ve given them good testing and considered things like reliability, build quality, performance, and how easy they are to set up and use.

Comparison table: Best Pond Filter Box Reviewed UK

ProductWhat We ThinkPrice

All Pond Solutions Small Fish Pond Filter Box - Full Kit - 9w UV 2300L/H Pump hosing and clips.

  • Pond Filter box / 2300L/H Pump / 9w UV / Hosing
  • Clip on removable lid with built-in 9w UV steriliser
  • Includes japanese matting, coarse / fine foam
  • Thermometer / dirty filter indicator built into lid
  • Dimensions: 400 x 275 x 400mm (H x W x L)

Oase in-line filter BioSmart

  • Reliable basic in-line filter for ponds spanning up to 36 m³...
  • Easy maintenance - thanks to cleaning handles and base drain
  • Display of degree of contamination and temperature for comfortable filter monitoring

Fish Mate Pond Filters (5000 GBIO)

Fish Mate Filter 5000 GBIO

  • Biological gravity filter
  • Powerful 3 stage mechanical and biological filtration for optimal water quality and healthier fish...
  • Easy filter maintenance
  • Includes SUPRA+ bio media
  • 3 year guarantee

Swell UK Pond Filter Box Premium Kit 45000

  • This pond pump and filter kit is an extremely effective flow-through gravity filter to keep your pond clear and...
  • UV pond filter has an 36w UV light with an inspection window to clear green water from your pond...
  • The pond pump has a flow rate of 10
  • The pump and filter are low maintenance with a unique in-situ filter foam cleaning mechanism...
  • Provides peace of mind with a 1-year warranty on the filter and UV...

Fish Mate Pond Filters (2500 GUV)

Fish Mate Filters (2500 GUV)

  • Combined UV and biological filtration for crystal clear purified water
  • Flip up lid for easy maintenance
  • "Frost proof" quartz less UV chamber
  • Includes SUPRA+ bio media
  • 3 Year Guarantee

1. All Pond Solutions Small Fish Pond Filter Box - Full Kit - 9w UV 2300L/H Pump hosing and clips.

For smaller garden ponds, you won’t get a better deal than the All Pond Solutions small fish pond filter kit. Included in the box is the pond filter box, UV steriliser, filter foams, bio balls, pump, hoses, and all the clips and fitting you need to get set up. All of that for under 110 quid! Now that’s the kind of deal I like.

Now, with the low price you can’t expect an indestructible pond filter box, there aren’t any plugs on the cables, and if I’m honest, the outflow pipe was a little on the short side for me. However, this was an easy fix with an extra bit of pipe and a couple of plugs from the local B&Q, so I can’t complain too much. All being said, the quality of the kit in general is better than I would have expected for the price.

The pump that comes with the pond filter box has a flow rate of 2300 litres per hour, more than enough for any small fish pond up to  4500 litres, and capable of cleaning a 6000 litre pond if there are no fish.

As already mentioned, the filter uses a combination of UV light to clump the algae, then the water passes through the Japanese matting, then foam filters, and finally passes over bio balls, to give your pond water a very thorough cleaning and leaving you with a marvellously healthy pond.

Built into the lid of the pond filter box are a thermometer so you can check to see that there is no blockage, and also a dirty filter indicator that lets you know when it’s time to open up the box and give it a good cleaning out.

Maintenance is simple and easy with this filter box. The lid is removable; you just need to undo the clips, and there is a handy waste drain to help speed up the process.

For a little over a hundred pounds, you’d find it hard to get your hands on a pond filter box kit that works as well as this one, even if there are a couple of little niggles. If you want perfection, spend a lot more on a top tier filter, if you just want a cheap filter to keep your mall pond clean, this is a product for you.

Another excellent pond filter box is the Swell 45000 premium kit, available for just under 400 pounds. For that price, you get everything you could possibly need to keep your pond water crystal clear, and your goldfish or Koi healthy.

The economical pump has a 10,000 litres per flow rate, making it more than capable of servicing a fish pond of 22,500 litres. However, if you have a koi pond, that number shrinks to 11,250 litres. Still, this makes it a good choice for small to medium sized ponds.

A 36-watt UV light is incorporated into the pond filter box to give you even more pond cleaning performance and will soon have you smiling back at your reflection as the water quality improves. The filter uses a foam cleaning system which is simple yet effective, and this makes the whole system easy to set up and maintain. You can simply remove them from the box and squeeze them clean. 

In addition to being cheap to run, the pump has been designed to be durable and low maintenance, and comes with a three-year warranty for your own piece of mind. What I like about this particular pond filter box, is that it has been designed to clear waste and debris from the bottom of the pond that would normally settle there and fester. Debris measuring up to 12mm in diameter can easily pass through the filter and this equates to a really healthy fish pond.

As a safety feature, this Swell pond filter box has an automatic thermal cut out that will automatically turn the pump off if there is a blockage that causes it to overheat, or if it runs dry. If this happens, you just need to clear the blockage and the pump and filter will run as normal again. 

A 10 metre pump cable is included in the box but no plug, so you’ll have to fit one on yourself, but that’s pretty much the only fault I could find with this excellent pond filter box.

Swell UK Pond Filter Box Premium Kit 45000

3. Fish Mate Pond Filters (2500 GUV)

If your garden pond is on the smaller side, 2500 litres or less, The Fish Mate 2500GUV is a good low-cost option. Using a combination of biological, mechanical, and UV treatments, this model does a great job of purifying your pond water and clearing it of unwanted pollutants and debris. 

When I first got my hands on this pond filter box, I can admit to being a bit skeptical. This was largely due to the compact size of the box, and of course the fact that it only costs around 70 pounds. I have to say though that I was very wrong. This little box worked really well once attached to a pump and a little fiddling around to get the water flow just right. Thankfully there is a water flow gauge to help out with that.

The UV lights clump the algae as well as much more expensive models, and the fact that the UV chamber is ‘quartz-less’ means that it is less susceptible to damage from frost. Something we all need in the British Wintertime.  Included in the price are the filter foams, and also the ‘SUPRA+’ biological filter media that will promote good bacteria to flow back into the pond and keep it healthy.

The Fish Mate 2500GUV is an easy filter box to clean and has a hinged lid just for this purpose. If your pond is looking pretty green and grim, I would suggest cleaning out the box every day or two until the water is clearer and then you can do it less often. The cleaning process can be taken care of in a few minutes, so there’s no excuse not to keep on top of this, and it’ll keep the unit working optimally, providing you with the best results.

There is a multi-sized inlet (19 or 25mm) and this helps you to get a better seal with your chosen hose. There aren’t any clips or other fittings with the filter box, so you’ll have to spend a couple of quid on those, and of course buy a suitable hose too.  Even after buying the extras, this is still a very low-cost pond filter box and it is surprisingly good. Just don’t expect results overnight. These things take time.

The Oase 36000 BioSmart in-line filter is a good buy if you don’t mind spending around three hundred pounds. This pond filter box gets its name from the fact that it is suitable for ponds up to 36000 litres if there are no fish, and obviously less so if there are some.

It is an extremely solid and well built filter box for the money, and also incredibly reliable. A friend of mine has had this exact same model in their medium sized pond for over two years now and he swears by its durability, saying that he rarely has to perform any maintenance on it, and even when he does it’s just a bit of cleaning.

Cleaning this model is straightforward, and made even easier thanks to a well placed base sludge drain and cleaning handles. The Biosmart 36000 uses large surface area foam filters and biological filtering, and it works a treat, removing large particles from the pond and giving you perfectly clear water with a high level of oxygen enrichment in return.
Situated on the filter box is a water temperature gauge and a contamination level meter, allowing you to monitor the performance of the filter and the state of the pond water too.
This is a fairly big unit, and with that comes a bit of extra weight too (10.7kg), but this just reinforces the idea that this is a solidly built piece of kit that is made to last. Unfortunately, the pond filter box doesn’t come with a UVC, but OASE does make one that can be bought separately and can work in conjunction with this model.

Once you factor in the rice of a pump, hoses, and the UVC, this isn’t a cheap option, but with most things you get what you pay for, and this is an excellent garden pond filter box that’ll last years.

Oase in-line filter BioSmart

5. Fish Mate Pond Filters (5000 GBIO)

Our last review for today is of another low-budget, yet well performing pond filter box from Fish Mate, the 5000 GBIO. Despite its price tag, that hovers between 35 and 40 pounds, this biological gravity filter performs exceptionally well at its designed task, making full use of a three-stage filtering system to clarify your pond water.

It features the same foam filters and SUPRA+ bio media as the 2500GUV model we reviewed earlier, and both come in the packaging along with the filter box itself. And just like that model, it is claimed to be also suitable for small ponds up to 5000 litres in volume, but I would say it’s best for smaller than that to be honest.

This unit is best used with a 2,000 litre per hour pump, but you’ll have to buy that separately, along with the necessary hoses and fittings. It does, however, feature double outlets which can allow you to use a more powerful pump without overflowing, within reason, obviously.

There is no UV lighting with the 5000 GBIO, it is just a basic mechanical and biological filter, but it still does an admirable job if operated and maintained properly. You can always buy a separate UV box to use in tandem with the filter if you really feel the need to.

You’ll have to keep the unit and the foams cleaned regularly, especially at first until the water clears somewhat, but like with most of these kinds of filters, it’s a quick and easy task that doesn’t take long.

Likewise, setting up and installation of the 5000 GBIO is a piece of cake as long as you have gone out and bought the proper sized hoses and connectors, but any decent pond shop or garden centre should be able to help you out with that.

Once properly set up, you should see visible results within a week, and really clear water after 2-3 weeks, as long as you keep the machine cleaned out of debris. This is a cheap but effective prospect for people with small ponds who don’t want to spend too much on their filter system.

Best Pond Filter Box Buyer’s Guide

Filter box only or full kit

Before you go ahead and click buy now on your pond filter box of choice, make sure you know what you’re buying. Some models are sold as just the filter box only, while others are the full kit and include the pump, hoses, and fittings. This is important, not only because a box without a pump is pretty useless, but because a product that seems like a great deal might not be once you figure the cost of buying a pump and hoses separately. 

How easy is the box to maintain?

While most filter boxes are quite easy to maintain, and that’s one of the biggest draws of this type of filter, some are even more so than others. Pond filter boxes that have features like cleaning handles (for squeezing the foam filters) and sludge drains can make cleaning the box a much less messy affair, and this can be important to some people, especially when you think that you’ll have to do very regular cleaning when you first install the filter, at least until the water is clearer.

UV lighting

Some pond filter boxes come with UV lights already installed, and this is a good thing. UV light is used by pond filter makers because it helps to clump the algae together, and this makes it easier to collect and get rid of it. UV is excellent for dealing with what is called ‘green water’. Basically pond water that has a lot of algae and has turned green and smelly, and so it is a much sought after feature. Not all pond filter boxes have integrated UV lighting though, and you may have to buy it separately, increasing the overall cost to you.

The size of your pond

There are pond filter boxes that are designed for small, medium, and large ponds, and you’ll need the right size to get the best results. You also need to factor in the number of fish you have in that pond, as more fish means more waste to be filtered, and so you’ll need a bigger filter box. Most pond filter boxes will indicate in their name the size of the pond they are best suited too, or you can find it I the product description on their Amazon page, but this number is usually based on a pond without any fish, so you’ll need to do a bit of calculating, especially if you have a koi pond.

Read reviews of the product you are interested in

It’s always best to read multiple reviews from sites like ours, and also from customer feedback to get a good idea of the pros and cons of a model that you’re interested in. Don’t be turned off by one or two reviews though, everyone has their own opinions and experiences, and people with bad ones are more inclined to leave reviews that people who are happy. Weigh up the positive and negative feedback and then make up your own mind.

About Terry Smith

I’m Terry Smith from gardentoolbox.co.uk, a professional landscape designer, hobbyist gardener, and barbecue fanatic with 20 years experience building and restoring. So as you go through my site you'll watch me document some of the professional garden installs I make as well as the major projects I take on at home. While sharing those experiences and guiding you, I'll be recommending some great tools I use to enable this along the way so you can really buy in confidence. Always feel free to pop me a message: info@gardentoolbox.co.uk

View all posts by Terry Smith

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