The pond filters are a bit of a minefield. You look online, and suddenly, a hundred different boxes are claiming to be the best thing, and you may be totally confused about what to choose. It is enough to make your head spin. I remember setting up my first pond and just guessing. Worked out fine eventually, and after some mistakes, you know how it goes.
Let me tell you about something that would have saved me years of hassle, though. The Evolution aqua Nexus 320 titanium with UV available at That Pond Guy is basically the Rolls-Royce of pond filters. They are built right in. The titanium finish means it does not go all chalky and faded after a summer in the sun, either.
My neighbour got one last year. Does not shut up about it. To be fair, his water does look like drinking water, and mine sometimes looks like weak tea.
Mechanical Filtration – The Net
This is the simple one. Water pushes through foam pads or brushes. The pads catch the solid fish poo, leftover food, bits of algae, all that brown gunk.
- Needs cleaning. Like, regularly. Squeeze those pads in a bucket of pond water. It is grim but necessary.
- Pads wear out. Replace yearly. They go bad and stop working.
- Won’t catch everything. You still need to net out leaves and stuff manually.
Biological Filtration – The Bacteria Bit
This is where the magic happens. Inside these filters, you have plastic media, little balls, noodle shapes, K1 stuff, covered in good bacteria. Billions of them. These tiny guys eat ammonia and nitrites. You know, and the toxic crap fish produce constantly.
- Takes time to establish. Weeks. You cannot rush bacteria.
- Runs constantly. Needs air flow. Cheap to run though.
- This keeps fish alive. Seriously. Don’t skip this bit.
UV Clarification – The Green Water Zapper
Not technically a filter. It is a tube with a special light inside. Water flows past. Light kills the single-celled algae that turns ponds green. Dead algae clump together, get caught in your mechanical pads, and you scoop them out. Job done.
- Stops green water dead. Works fast. Like, days are fast.
- Does not stop blanketweed. The stringy, hairy stuff and UV won’t touch it.
- Bulbs die. Replace yearly. They just stop working, and you won’t notice until your pond is green again.
So, What Do You Actually Need?
All of it, and in an ideal world:
- Mechanical first. Catch the solids.
- Biological second. Process the invisible nasties.
- UV somewhere. Stop the algae from turning everything green.
Some fancy all-in-one units do this. Saves messing about with pipes and multiple boxes. Worth the money, honestly.
One Last Thing
Get the pump size right. Too small, then nothing filters properly, and too big, then stressed fish and a washing machine effect. Just check what your filter recommends. Honestly, filters are not scary once you understand them.
Mechanical catches visible gunk. Biological sorts invisible nasties. UV kills green water. Get them working together, and you will be smiling.