# DIY Fluidized Sand Bed Filter



## Bartash (15 May 2012)

Disclaimer:
I accept no responsibility for any damage or injuries you may sustain whilst using this walkthrough. This is for informational purpose only and may not be reproduced without my permission.

I’ve seen several videos on YouTube where people have made a fluidized sand bed filters but I have not really found much information on how to construct one.
I’m going to show you how to make one very cheap that will work a treat.
I’m making one with bits and pieces that I have lying around but I will do my best and try to use items easily obtainable.

How does it work?

Water enters the canister at the bottom of the sand and agitates the sand so all the particles move around; this allows good bacteria to colonise on the surface of each particle of sand. The water then exits through a tube at the top of the canister and back into the tank. 
This type of filter is far superior to any other type of filtration (in my opinion) as the greater the surface area that bacteria can stick to the greater amount of bacteria are contain within the canister eating ammonia. As the particles are bashed about weaker bacteria is knocked off only leaving the more hardy bacteria behind. 

Things you will need:

Large glass jar
2x 12mm threaded barbs (plastic if possible)
some 12mm ID tubing
aquarium silicon
Power Drill
12mm drill bit
PTFE Tape

I use a glass jar as my canister but if you can find something with a watertight top that is fairly rigid to hold your threaded barbs.







OK what you need to do is drill 2 x 12mm holes into the lid of the jar using the 12mm drill. 12mm holes are perfect for me to screw the threaded barbs in. Depending on the thread of the barbs you get you may need to make the drill holes smaller or larger so your barbs screw in nice and tight. One of the holes needs to be in the centre of the lid and the other hole to the side as shown in the picture.





Once you have drilled the holes you need to screw in the barbs being careful not to over tighten as the jar lid is very thin. 
I am using some barbs I had lying around one is brass and one is chrome but I would recommend you use plastic barbs which I’m sure you can find online quite easily.  






Then you need to measure a length of 12mm tubing that will stop ½” short of the bottom of the jar, this is to make sure the water can freely exit the tube and agitate the sand. 






Then you can go ahead and attach the tubing to the underneath of the lid on the centre barb





Being the cautious person I am I needed to make sure that there is no way that the water can leak through the jar lid. Mount your aquarium silicon into a mastic gun and add a nice bead around the underneath of the barbs and also on the top of the jar lid. I dint have any aquarium silicon to hand so I just used all-purpose silicon for demonstration but I strongly advise you to only use aquarium silicon. Wet your finger and smooth it around a bit to make sure it all seals nicely.











Now you need to be patient and let the silicon cure for the recommended amount of time on the silicon tube. If you don’t wait until it is cured you may end up with leaks, so don’t try to rush curing with any heat source as you may shrink the silicon and break the seal. 
The next step is to make sure your jar remains watertight so get the PTFE tape and wrap it around the thread of the jar, you could also use aquarium silicon if you wish as maintenance will not really be required.






You should end up with something that looks like the picture below






Ok now for the sand, different people like to use different sands in their filters. The most popular sand to use is silica sand; this sand is very fine and works really well. I tend to use slightly larger grain sand because I prefer the bashing around motion more than the truly fluidized motion.
You need to funnel sand down the water outlet barb; this is the barb that is not connected to the tube inside the jar. Fill the jar so it is about 1/3 full, if you put any more than this you risk the sand being drawn up through the water outlet and into your tank.






Now it’s time to test your fluidized sand bed filter, the easy way to test is to take it outside and attach your garden hose to the water inlet barb (the one connected to the tube inside the jar) and a bit of 12mm tubing to the water outlet barb so that the water does not just shoot upwards as it exits the jar. Turn on the water tap slowly so that you can see it moving the sand around, if all goes well you should not have any leaks and the sand should be agitating nicely.
You may get some small light particles of sand exit the jar at first but after a few seconds it should settle nicely. 
I have uploaded a video to you tube showing the jar in this walk though working so go check it out.

http://youtu.be/hJ7jbq_AhcY

Additional info:

This is a biological filter so should not be used to collect tank debris, try to use this inline after your mechanical filtration.
After a while you will see the sand changing colour eventually going a dark brown, this is good news and what you can see is good bacteria on the particles of sand. 
Maintenance is not really needed, but if you find the sand starts to become to static and gungy then do a 50/50 change. Take out 50% of the old sand and add 50% new sand this will ensure you still have good bacteria to replicate. I doubt you will even need to do this.

I hope this has help many of you out and remember this is just how I do it; you may find something other than barbs you can use or a different way to do things. 

Thank You

Carl


----------



## Kristoph91 (15 May 2012)

Very useful Carl, I'm sure lots will try this. Does the sand never get sucked out ?


----------



## Bartash (15 May 2012)

I does not get sucked out as long as you don't over fill with sand, 1/3 is about perfect.


----------



## Kristoph91 (15 May 2012)

Interesting! thanks


----------



## Mar10 (22 May 2012)

Thanks for this Carl,
 I am interested in doing this myself, what is the output of the pump you are using?
I have an Eheim 1060 with an output of 2200l/hr which I am concerned may be too much.


----------



## Bartash (22 May 2012)

yeah i think that will be far too much, im just using a 700L/H at the moment, if you managed to get a larger container to build your fluidized sand bed then you would be able to use greater L/H. Im planning on making my own container out of clear perspex tube 80mm x 500mm when i can afford to buy the stuff lol. 

If you are interested in making your own then check this out:

http://stores.ebay.co.uk/Clear-Plastic- ... 4340.l2563

you can buy everything you need to make it from him except the plastic barbs



Carl


----------



## Mar10 (22 May 2012)

Thanks again Carl,
 I have a couple of screw top, tupperware type cannisters that I bought from Poundland some time ago, I think I will dig these out to assess their suitability and maybe connect it to the output side of my Eheim 2213 cannister filter. This has a rather poor output, around 500l/hr IIRC, however, as the fluid bed is so much more efficient, the low output should not be an issue, I can then continue to use the 1060 for circulation during the day, when the CO2 is on.


----------



## Aqua sobriquet (22 May 2012)

You can get these from about a tenner. Should be quite easy to mod:

http://www.ebay.co.uk/itm/Water-Filter- ... 1070wt_689


----------



## Mar10 (22 May 2012)

Interesting, 3/4" outlets may be too big, well worth considering though


----------



## Aqua sobriquet (23 May 2012)

Mar10 said:
			
		

> Interesting, 3/4" outlets may be too big, well worth considering though



You can get them with different size outlets. I think the smallest is 1/4" but you can buy adaptors anyway though so it's not a problem.

http://www.waterfilterman.co.uk/ten-inc ... 20136.html

These things are designed to take several bar of mains pressure so aren't likely to leak for our use.
I would advise buying a spanner though as they can be a bit tight sometimes


----------



## Mar10 (23 May 2012)

Aqua sobriquet said:
			
		

> Mar10 said:
> 
> 
> 
> ...



The more I look at it, the more I am drawn to it so I reckon this is the route I'll go.
Good find, thanks mate


----------



## Aqua sobriquet (23 May 2012)

No problem. Lets see some pics if you proceed!


----------



## Mar10 (23 May 2012)

It's a deal, when I get all the bits together I will report back.


----------



## sr20det (23 May 2012)

Aqua sobriquet said:
			
		

> You can get these from about a tenner. Should be quite easy to mod:
> 
> http://www.ebay.co.uk/itm/Water-Filter- ... 1070wt_689



I think i have 3 of those, planned to use for filtering rain water.  Think I only need now.  Might use one for sand.


----------

