Pond Filter DIY

Luc70

Dovii
MFK Member
Jan 8, 2009
729
353
102
Bangkok, Thailand
After getting the pond running at my brother's house, though not 100% complete yet, I decided to start a long overdue filter upgrade for my small pond at home.
The pond is about 1.30m deep, 2m long and 1 meter wide. It had one of those blue barrels, filled with bio-balls and it was a pain in the ass to clean, with rubbish settling at the bottom.

So my ideal filter is:
1. Compact
2. Very easy to clean
3. Loads of media for bacteria to sit on
4. Easy to clean
5. Cheap to make
6. Easy to clean...
7. Modular and future proof (like adding more media)

Obviously, I hate maintenance and cleaning.. So a filter has to be.. ok ok.. you get it already..
Still.. I'd like to add.. easy to clean...

I've been looking at all those nice Bakki showers and what not. Way too expensive of course, and even self-building would require loads of big bins/tubs
That's going to be a pain in the ass to..well.. clean..

Space is at a premium, so I decided to go with stackable crates. The warehouse type crates.
I could have gone with some bigger storage bins, but that will be monstrously big, and you're limited in how and which media to put in.

IMG_2536.jpeg

Crates.. Blue or green. I liked the green color. 145mm high, 620x410mm. Perfect.
There's several things I want to build in.
- Top layer: 300 micron sieve and filterfloss below it.
- Middle layer: 40 ceramic rolls and the remained is filled up with bio-balls
- Bottom layer: Bio-balls and the outlets.

IMG_2544.jpeg

I checked and choose crates that have a 'webbing' in the bottom. This will make drilling holes very easy. Each square one hole.
After that, turn the crate around and go over each hole with a reaming bit? not sure what they call it in English, but it takes away all the sharp corners and makes it easier for water to flow.
My crates had openings for handles. So I epoxied some Plexiglas in to close the openings and it allows me to look inside each crate.

IMG_2546.jpeg

Took me an hour or so to drill all the holes in 2 crates. Obviously, the bottom-crate is not drilled.

IMG_2555.jpeg

Here's the Plexiglas openings.

IMG_2545.jpeg

And the ceramic 'rolls'. Rest of the crate has been filled up with bio-balls.

IMG_2550.jpeg

Bottom Crate, I've added 6 airstones.

IMG_2551.jpeg

This is the top crate. I've used 300 Micron sieve and it's attached to a piece of aluminium to keep it up from the bottom. The aluminium is bolted to the bottom of the crate.
Filter floss below it, to add more space for bacteria and to scrub the water even further.
The sieve just folds back over it and is attached to the edge of the crate with 2 bolts again.

IMG_2552.jpeg

Here it's complete, the sieve folded back and a temporary setup of the pump outlet over it.
Still want to clean that up a bit, but that's for later.
Now, the nice part is the filter floss at the bottom of the picture. This is separate from the floss in the previous picture and just sits there to trap any solids coming off the sieve.
The sieve angle is very shallow, but I just use a bottle of water or a hose to wash the solids down into the floss.
Take out the floss, rinse the solids out or just replace with a new piece.. that's all there is in cleaning..

IMG_2556.jpeg

And voila. A working and fully functional filter!

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And a peek inside while running. Nice spread of water running down evenly.

Now the good thing is, I've left some slack in the hose from the pump.
So I could just lift the top, add another crate to the stack in 5 minutes.
Or how about populating a filter for another pond or tank?

Overall, looks like a winner for my targets. Will update with some more observations over the next couple of weeks.
Might order another couple crates, one for media and the other to use up-side down as a cover..
Tomorrow spend some time on the pipes for the pump. Electrical will be upgraded as well when I receive the parts.

IMG_2562.jpeg

And after 2 hours, flushed down the gunk with a bottle of pond-water.

Cheers,
Luc
 

Luc70

Dovii
MFK Member
Jan 8, 2009
729
353
102
Bangkok, Thailand
Just to add, took about 5 hours to get everything assembled and installed.
So far, lots of gunk on top the sieve, so I'm very curious how it looks tomorrow morning.
The sieve curls up at the sides, which is nice as it keeps the gunk on top of the sieve and floating down.

Cost:

Crates: 28 USD
Ceramic Bio Media: 45 USD
Fittings: 3 USD
Sieve: Rest piece from earlier order.
6 Air-stones: 2 USD

Of course, using lava-rock or other cheaper media will bring down the cost considerably.
You could also mix different size crates, more space for bio-balls, for example, or steeper sloped sieve in a deeper crate.
With those industrial boxes, there's quite some mix and match possible.

Overall, very cost-effective and easy to build.

Cheers,
Luc
 

esoxlucius

Potamotrygon
MFK Member
Dec 30, 2015
2,389
5,695
164
UK
That's a great build. I also have a plastic crate tier system on my 360g. One of the major issues with all aquarium mechanical filtration is that, yes, they take the "bits" out of the water column (down to a certain size anyway), but these bits usually just sit in your sponges then, further breaking down and polluting your water, until they're removed/cleaned.

That sieve you've got going on there, due to the angle it's at, takes the waste away and it just sits on top and is very very easy to wipe off. It's not in your sponges polluting your water anymore. That is key to overall better water quality.

I've been thinking of rehashing mine to incorporate a similar sieve system. The beauty of it is you can go down in micron size even further, and adjust the angle of the sieve accordingly to maximise finer particulate removal.

A question for you. Why do you feel there's a need to put airstones in that bottom crate? I could understand it if the crate was submerged but it's not. What's your thinking?
 

Luc70

Dovii
MFK Member
Jan 8, 2009
729
353
102
Bangkok, Thailand
Thanks for the reply Esoxlucius.. The sieve indeed takes out loads of solids.
Did get problems yesterday though. Due to its 300micron size, it clogs up easily.
What happens is, the fines start clogging the sieve and water runs over it instead of through it.
It's not a big problem, simply requires daily cleaning with a garden hose spray head. 10 seconds and done.
Will keep watching it for the time being, see how it goes.
This might have to do with the shallow angle, so might change the sieve temporarily to see how it performs.
For sure, I'd not go any smaller than the 300 micron right now. Rather a 100 or 200 micron I think.

Will update soon again on that.

The next part is the airstones. I had the pump and thought why not.. its only a 40w pump, and there is a bit of standing water in the bottom crate, so with the airstones, at least small fines and other gunk will be lifted up and pushed around. And even if only a little bit, it still helps aerating the water.

Cheers,
Luc
 

fishdance

Peacock Bass
MFK Member
Jan 30, 2007
1,266
279
122
Filter looks good. Top effort as usual.

It's not worth the effort but if you were to submerse the bottom most tote, you would get full counter current air exchange (air is forced up against descending water) which is 5 X the efficiency.

Also your seive is always going to quickly clog due to biofilm build up. You could use wedge wire (quite expensive) or add a naked UV lamp (potentially dangerous to eyes of unwary & may harden the plastic) or use several layers of Japanese matt.

The Japanese matt is rotated weekly with the soiled top layer soaked in bleach for the week to destroy organic buildup. Easily shaken and rinsed clean before use. The idea is not to catch all the fines so it doesn't clog too fast and require more maintenance, it's just to remove most of the detritis from the water column so your filters don't need to work as hard.

Or you could make a slow self winding roll of dacron. Probably quite wasteful but new media prevents biofilm buildup.
 

fishdance

Peacock Bass
MFK Member
Jan 30, 2007
1,266
279
122
I probably should add that the system I'm currently using for mechanical prefiltration is one of those blue barrels you used to use. I fill with micro K1 media used as static media. Just pour the water through the media. When the water starts to pond up, its becoming dirty & clogged. Very easy to clean with a flood, stir and dump to waste. You need at least 50cm media depth and less than 10,000 LPH flow in most situations.

I've experience with all the ideas I previously mentioned and I'm saving up for the wedge wire.
 
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