"Fish2Keep" wrote in message
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"NetMax" wrote in message
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"Bill Stock" wrote in message
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"NetMax" wrote in message
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"Bill Stock" wrote in message
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"Fish2Keep" wrote in message
k...
"Bill Stock" wrote in message
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I've used both Ehiem and Fluval canister filters, I would rate Ehiem
as being much better. The problem with the fluval canister filters is
the water can flow outside the baskets

Usually on the floor. (Kidding)

meaning the water is not filtered as well as how the Ehiem's work.

I've read this a few times, but I wonder how signicant this is. It
would be interesting to do a controlled test to see how both filters
performed with varying particle sizes, given the same flow rate.


For no-bypass systems (Eheim), I think the advantage is a higher
filtration efficiency (particle removal efficiency as a function of
water volume moved) but the disadvantage is there is a greater
difference in flow rates from empty to filled, and in a worst case
condition, your nitrifying bacteria could die off if the water flow was
too low. Generally requires a pump with higher head pressure to
compensate for this (push through the obstruction), and the impeller is
(in theory) designed to free-spin (spin without damage in the absence
of waterflow).

By-pass systems (Fluval), conversely would have to move more water to
achieve the higher efficiency, but even if the filter is clogged, the
bypass ensures there is always a minimum water flow. Early Fluvals
would still have a nitrifying bacteria die-off (the bypass went around
the sponges), but the current Fluval's bypass keeps the bacteria in the
main sponges alive. Generally this requires a less fault tolerant
(less expensive) motor/impeller design, as there is less likely to be a
significant reduction in flow (which acts as a coolant to the motor).


Any idea what percentage gets bypassed on the various Fluvals?

Nope, but it would be variable to the amount of back pressure caused by
the build-up in the filter stages.
--
www.NetMax.tk

With ideal maintenance: the Eheim is slightly better.
With normal maintenance: comparable imo
With poor maintenence: the Fluval is slightly better.

In other words, a dozen of one, or twelve of another ;~) ...but it's
still fun to watch the hype at work ).
--
www.NetMax.tk

http://www.fish2keep.com
Share your fish keeping skills!!!










Everybody is different, I've used both types "Fluval and Ehiem" and would
rate the Ehiem's as a better overall canister filter myself. But each to
there own..
--
http://www.fish2keep.com
Tropical | Marine | Coldwater
Community Forums


Absolutely, and we aren't even discussing all the other factors which make a
filter good or bad. In the 70s, I would have gone hungry standing on a
soapbox complaining about all the filter defects and crappy designs. Today
there is a lot less to complain about, making the differences between
manufacturers smaller and smaller. My personal favourite filters are not
Fluval or Eheim, but matt filters, but I put up with canisters for their
convenient (plug & play).
cheers
--
www.NetMax.tk