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DIY Fluidized Sand Bed (Biological Filter)

By Jim Chitty

I ran across a Youtube video on the DIY Fishkeepers (Joey) and remembered I had a commercial version of one of these about 15 years ago. It worked ... but it was a pain to keep properly running. I had most of the parts and decided to make a few of them with a couple of modifications.

Here is the Youtube video.

Here are the parts that I used and their approximate cost.

Maxijet 600 power for around $18.

1/2" CPVC pipe. You can get this at either Home depot or Lowe's. Lowe's has it in 5 foot sections for around $3.50. I also found it at Home Depot in 24" lengths for just under $2.00.

Of course, you can buy it in longer lengths.

CPVC end cap $.25

CPVC 90 degree connection around $.60

Glass jars. 3 1/4 inch diameter and either 9 inches tall or a shorter one, just over 7 inches for a whopping $1.00 at the "Dollar Store".

Egg crate material

Plastic wide mouth mason jar lids. Target has them 6 for $3.95.

Mod 1 - The only modification was the lid. I did not like the plastic mesh that was shown in the video. I tried it, but it seemed that it was not stable. I had to use a dremel tool to remove the threads on the lid as it was just a tad too small to fit over the glass jar.

Mod 2 - I realized that the intake and water output were too close together. So I extended the intake as shown. I also did not like that the tube inside the glass container could shift against one side of the glass container if moved. So I built the following to hold it centered.

I used the dremel tool again to carefully make a circular center that could slide onto the CPVC pipe and sit above the end cap. This mod apparently did not hamper water or sand flow.

Basic construction was pretty much the same as the Youtube video. The end cap had 4 1/4" holes drilled in it. The plastic lid had a 1/2" hole drilled in the center. Then the dremel tool was use to wide the hole slightly so that the 1/2" CPVC pipe could slide through.

8 1/4" holes were drilled in the perimeter of the lid.

Final assembly looked like this.

Here are some brief videos of filters...


Fluidized sand filters have a large surface area. Bacteria will coat the sand in 3 to 4 weeks and provide superior biological filtration. This would be great for the breeders in the club that have a high biomass (lots of fish) in grow out aquariums. I would use this type of filtration NOT as my main biological filtration...but to supplement my current filtration in my tanks.


Power failure! If you should lose electrical power for more that a few hours the bacteria will die. For me ... luckily in the past 20 years I have only had 4 instances where we were without power for a significant amount of time.

Possible overturning of filter. For one ... the lid modification should keep most of the sand intact and two ... the suction cups that come with this filter will hold this in place without much trouble.

Now how much should this handle? Internet indicates that 1 pound of sand should handle around 100 gallons. Both these filters are currently using just over 1.5 lbs or 150 gallons.

Joey stated that a pump with an out put of 100 gallons per hour should handle 1 pound of sand. He was right on the mark! Maxijet 600 used has an output of 160 gallons per hour and I am using just over 1.5 pounds.

Now here are a couple of OTHER uses for powerheads. Most water bottles will fit over the intake. Cut off the bottom of the water bottle and attach it to the intake. Place some filter floss in and now you have a power filter.

Turn it upside down...cut some slits in the top and have it at the surface of your aquarium and you now have a surface skimmer! ( Great for people with duckweed problems..especially me.)

For more information on this type of filtration, just Google "aquarium fluidized sand filter".

If any questions, don't hesitate to ask!

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