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Re: Fluidized Bed Filters
> > I haven't seen much discussion here about fluidized bed filters. My
> > local fish store owner thinks this would be a better choice for a CO2
> > injected tank than a trickle filter. His rational is there would be
> > less CO2 loss due to outgassing.
> I think this is true if the water return was below the surface to
> avoid turbulence. I assume they also generate good water flow? (They
> need more water flow than normal to keep the bed "fluid", right?)
Actually, the ones I've seen and used all produce very poor water flow
(<100gph). I have seen the QuickSand brand and I own a Merlin. They
require quite hefty powerheads to keep them operational but output VERY
little water. I suspect the additional head of the sand filter really
gives these little powerheads a run for their money.
> However, I see some potential downsides.
> What about mechanical filtering? Is there a prefilter of some kind?
> Or does the bed do the mechanical filtering? I've always assumed they
> were best at lots of biofiltering in a small space.
Generally a sponge prefilter is required or at least recommended.
> What about power failures? I've heard they good sour quickly when the
> power is lost because they compact quite a bit with no water flow.
With my Merlin a prolonged power failure (>5min) is generally disasterous
unless I'm around to fix it. The sand will become very compacted very
quickly and the little powerhead cannot make the sand fluid again without
manual intervention. What I have to do is open the flow restrictor until
enough flow is generated to kick start the sand into motion and then I have
to re-adjust the flow. It's a pain in the butt actually. For this reason
my Merlin is not in use.
> Do you think you need that much biofiltering in a planted tank?
I suspect this much bio-filtration is unnecessary and not the best
filtration option for a planted tank. They are VERY easy to maintain
I am in the trickle filter camp. Actually I think a Berlin style sump
would be more appropriate as a large bio-filter is probably not necessary.