homemade fluidized bed filter

[roliva]

Hello all,
I have recently made a homemade fluidized bed filter. The unit is pretty tall and holds about 5 lbs of pool filter sand. I am using an aquaclear 802 powerhead on it at maximum flow (400gph, I think) and it fluidizes the sand well and does not escape into the tank at this flow rate because the unit is so tall.

I am wondering is the flow rate too fast that the bacteria may not be able to attach to the sand and should I slow the rate down just enough for fluidization or leave it like it is?

 

[lee914]

Can you share your plans? email me, I would love to build one as well. To asnwer your question, no, it would not be too fast.

 

[roliva]

I'll whip something up as soon as I can. As far as the flow rate, I have found an informative reply from Grant Gussie:

Yes it certainly is possible to reduce ammonia conversion by making the fluidation too strong. The reason is
the faster the sand grains are moving the more they abraid each other,
which makes the bacterial coat slough off. So if the sand seems to be
blowing around inside you filter rather than circulating around in it
you may want to dial the pump back a bit. As I understand it, you want
the volume of the fluidized sand to be less than double the volume of
the settled sand.