How to design a FDF?

[Raven_]

Hi, going to build a fdf filter and use an eheim 2213 to power it and flowrate will be around 350-390L/H (92-100gph).
Will be placed within the tank and have a height of 40cm(16inch).
But i have some questions on how the design should be so came here in hope of getting them answered.

Will be built so its wider at the top then bottom to slow down the speed of water and thus prevent the sand from floating out.
But is there any practical difference between the 2 designs on the picture?

Does it matter if the shape is circular, rectangular or square?

Roughly how large bottom area should i aim for when using fine sand?

Want to connect the fdf to the suction side of the filter which will be stored on the floor below the aquarium, but will the filter create enough suction to keep the sand fluidized?

Water will probably flow in at the bottom but does it matter if the water flows in gently or violently?

Can an airstone at the bottom be used to keep the sand moving and oxygenated when the filter is shut off for maintenance?

Could an airstone be used to soften the sand if the filter doesnt have enough strength to get it moving by itself?

Regards

 

[justin guest]

Maybe this thread wiil help

http://www.monsterfishkeepers.com/forums/showthread.php?t=195926

j<><

 

[Dr Joe]

But is there any practical difference between the 2 designs on the picture?

#1 has dead spots where the size steps out.


Does it matter if the shape is circular, rectangular or square?

Not as lonh as you can keep the sand fluidized.

Roughly how large bottom area should i aim for when using fine sand?

That will depend on the size of the tank your filtering and the strength of the pump.

Want to connect the fdf to the suction side of the filter which will be stored on the floor below the aquarium, but will the filter create enough suction to keep the sand fluidized?

I don't think so.

Water will probably flow in at the bottom but does it matter if the water flows in gently or violently?

You won't have to much choice, the sand has to bre fluidized and not blown out of the fixture.

Can an airstone at the bottom be used to keep the sand moving and oxygenated when the filter is shut off for maintenance?

Temporarily yes, but since you are not feeding the filter when just air is being supplied you'll have a max of 10-15 minutes to work with.

Could an airstone be used to soften the sand if the filter doesnt have enough strength to get it moving by itself?

Yes, but I would use it as a constant source.

Dr Joe

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