Introduction
So as we all know the Fx5's design is not the very best for media capacity. I have been thinking of ways to improve this and some ways have been modifying the baskets but this would be way to much work and would still yield little increase in media capacity.
So I though, why use the baskets? They are only there to seporate the media and for ease of cleaning for the standard consumer. They are also to help with the air purging as well...
The modification that I have done has increased the bio capacity from 5.9L to 12 Liters or more. This is with 4" of mechanical foam. This increases to about 14 Liters when using only 3" of foam.
I use 4" of foam so I only have about 12L of bio media.
This modification is good for a few things.
1. ) Increase bio media capacity. Possibly around 12-15L
2. ) Decrease velocity of water flow for more contact time with bio media
3. ) Large area for flow which decreases the flow restriction.
4. ) Should help increase flow output since the water only has to change direction ONCE instead of THREE times.
5. ) Cleaning should be even easier and you will not need to remove bio media to clean the spunges like you had to before.
6. ) Eliminate about 5 possible warn o-ring issues
7. ) Original Foam blocks don't seal as nice as I would have liked to the basket above.
8. ) Increase the time between change intervals. In original form if you had fine filter foam in the center baskets, they could clog up real quick causing a drastic decrease in flow and lots of cavitation of the impeller and you would get LOTS of air bubbles everywhere. Should be able to use fine filter pads for longer periods of time.
9. ) Due to the decrease in flow resistance, hopfully this will help with the cavitation problem in the Fx5.
I may think of more reasons but so far this seems REALLY good.
Here are some updated figures;
Unmodified Fluval Fx5 Stats
Media Capacity: 5.9 Liters (im going to measure this since I think its wrong too..)
Mech capacity: 294 sq in; 369 cu in; 6 Liters
Measured Flow Rate: 525 GPH
Max Head Height: 3.3m (10.8ft)
Filtration Volume: 11.2 (Hagen says 20L. I call BS)
Modified Fluval Fx5 Stats.
Media Capacity: 12 - 14+ liters. (Depends on depth of mechanical filtration)
Mech Capacity: Est 108 sq in surface area. 325 cubic inches; 5.3 L (2" prefilter foam and 1" fine filter foam.)
Filtration Volume: 19.3L
Measured Flow Rate: ??
Ehiem Statistics
Eheim 2080 Media Capacity: 12 liters
Eheim 2080 Estimated Mech Capacty: 1.5L; 92 cu in
Measured Unmodded 2080 Flow: 318 GPH
Max Head Height: 2.2m (6.6ft)
Unmodded Filtration Volume: 13.5 L
Construction
The new design needed to be carefully thought out. I wanted the increased in bio capacity but also wanted a good amount of mechanical filtration. I wanted to increase area for increase in flow as well as an increase in volume for increase in media. I had to design it so the air purging could still work the way it should which took some rethinking and redesigning.
I used egg crate as seporation trays instead of the baskets and I order sheets of foam and custom cut them to fit for a 100% bypass free seal.
Im using Bio Bale as my bio media instead of the Fluval Bio Max which I have had great success with. The bio max would be way to expensive for the amount I need compaired to the bio bale which has TONS of surface area.
I had to keep the intake pipe submerged in water while the pump shuts off so the purging can work the way it should. I did not want the air to travel back through the intake. Only wanted it to go through the output. So I had to make a "pocket" for the intake pipe to sit into. This will also allow for a 180 degree dispersion of the water intake flow.
