DIY Fluidized Bed Filter: K1 Micro Media Aquarium Filter



TIP: Right-click and select "Save link as.." to download video

Initializing link download... Initializing link download.....

*FREE* downloadable content!
Get some K1 micro media:

Awesome air pump for this project:

Like I said earlier in this video I’m using K1 micro media that the pond guru was nice enough to send me. It’s got almost twice the surface area per volume when compared to regular K1 meaning you can get away with a filter almost half the size and still have the same capacity for biological filtration. If you’re interested in this media and want to help support a fellow YouTube fish keeper check out Richards channel and head to his eBay store where you can find this stuff for sale. Links in the description.
Ok, let’s Start by marking out a drilling a number of holes on the bottom portion of the bottle. There’s No real requirement here, I’m making 5 holes evenly spaced apart. Then mark out and drill two holes on one side of the bottle. Keep them more than a few inches apart as this is where we pop in the suction cups that will hold the filter to the aquarium wall. Drill one more hole near the neck of the bottle. This is where we’ll insert the airline so make sure to keep it a ¼ or so. If you make this hole the perfect size, there is no need for any silicone to hold it in place, although you always have that option.
Once that’s done, were then going to fill the bottle a little over 2/3rd of the way our k1 micro media. In this case it ends up being close to half a liters worth. I’ve found that most bottles out there will work pretty well with this ratio of media to volume but it’s also going to depend on a few other factors like air flow and bacteria load. Now attach the filter sponge to the bottle so you media doesn’t fall out and plug in your airline through the hole you made for it. Your internal fluidized bed filter is now complete so let hook it up to a tank, talk about how it works and also discuss pre cycling media.
Once you’ve picked out a good spot for your filter and have attached it, fire up your air pump to start cycling the media. Fluidized or moving bed filtration systems can be super-efficient for several reasons one, the constant bumping and circulation of the media will promote the growth of living bacteria that are capable of attaching to internal “protected” portion of the media. Two, the added air supply will greatly enhance the overall growth as well as the ammonia and nitrite oxidizing potential of the nitrifying bacteria making a home in your filter.
Because the moving bed media is close to having neutral buoyancy, it will naturally want to tumble thorough out the filter. If at first your media is not completely fluidized give it time as the buoyancy will slightly decrease as bacteria colonize it. However in most all cases, it just takes some extra air to get it rolling. Technically your only supposed to need close to 1.4 liters or air per minute to fluidize a liter of this media, although you can over load a filter like this so try and stick close to the 2:3 ratio of media to total volume to get the best effect.
If you have the time, you can pre cycle you media so that you’re adding in a robust community of bacteria right off the bat. To do this, simple add your media to a small bucket or jug. Fill with de chlorinated tank water, if you have some. This water will contain plenty of nitrifyers to get the process started. Add in an air stone and clamp it in place so I doesn’t float up to the top. Add in some liquid ammonium chloride and achieve somewhere in the ball park of 20 - 80 ppm total ammonia/ammonium. Simply put, the more you add, the more bacteria can grow. Now there will be a limit to this regarding the surface area and amount of media you’re cycling but it’s hard to go wrong here. Don’t worry about over doing it because in the lab we grow these bacteria in concentrations well beyond 100 ppm. I also like to add in a pinch or two of flake fish food to provide the bacteria with a source of phosphate which is also required for growth. Once the media has cycled completely, meaning NH3 and NO2- read 0, strain the media and add it to your filter. This process can take between 1- 3 weeks on average depending on multiple environmental conditions, the initial amount of bacteria and the NH3 concentration. No maintenance is required on this filter beyond removing and rinsing of the sponge every few weeks or as it’s required.


Some of our projects use materials and tools that can be dangerous. Our projects are meant to be fun and safe for all parties. If you decide to engage in any of our projects, remember you are doing so at your own risk. DIY AQUAPROS will not be held responsible for any personal injury or property damage resulting from any of our projects or instructions.
Be safe and enjoy !