From: pprior@magnus.acs.ohio-state.edu (Paul A Prior)
Subject: (FAQ) A proposed section - need help
Summary: LONG
Organization: The Ohio State University
Date: Tue, 15 Dec 1992 23:07:13 GMT


Below is a little bit of stuff I typed up to add into the FAQ.
Some of it is controversial, but I tried to be as fair and 
accurate as possible.  However, I would like comments/criticisms
before I submit it for formal inclusion.

Also, I am lacking some numbers in my chart.  If anyone could 
supply these it would be appreciated.

As if my mailbox needs any more abuse than it's already getting
from the survey...<G>




I would like to make a few updates/corrections/additions to the FAQ as
listed below:
 
---CURRENT FAQ SECTION:---
 
CANISTER FILTERS
     These are large plastic "canisters" typically located outside
of and under the aquarium in the cabinet. They are designed with a
powerful pump which draws water through an in-take hose located in
the aquarium, pushes it at a relatively high pressure through the
filter medium, and forces it back to the aquarium through the
return hose.  (Many times, this water is sprayed across the surface
of the water to create aeration).
 
 
------------------------
My proposed addition:
            --------
 
--------------ADDITION ----- ADDITION  ---- ADDITION  ---------
 
The question: Which cannister filter should I buy? is one of the most
frequently asked FAQs on *.aquaria and each time it comes up there
is discussion of the relative merits of each of the major brands.
 
General Comments:
 
Eheims:  The cadillac of cannister filters.  Very solid construction
    and operate virtually silently.  Significantly more expensive than
    other brands (see below).  Eheim recommends smaller models for
    larger tanks than the others and almost everyone buys larger than
    they say (2217 for a 55 gallon tank, for example, rather than the
    2213 which they recommend).  The Eheim cannister is a single
    hollow tube with water entering from a 90 degree tube at the
    bottom and flowing upwards through whatever you've packed in and
    pumped out the top.  They do not come with shut-off valves (a
    must-have for easy cannister maintenance), but these may be
    purchased separately (approximately $30).  Eheims have been dark
    translucent green with green hoses and black motor encasing.  The
    hose-clamping system is very solid.  Other options such as
    pre-filters, surface extractors and oxygen diffusors are available
    (and many will work with other brands).  They can also be ordered
    with built-in heaters (freshwater use only).  Made in Germany.
 
Fluvals:  Fluval filters have a slightly different design than the
    Eheims. Fluvals have the water enter and exit from the top of the
    filter. The entering water flows down around a central core which
    contains the filter media, and then returns up through that core
    to pass through the media.  The modular media containers which fit
    into the fluval filter allow for easy changing/cleaning off any
    segment of the media without disturbing the others.  However there
    may be some small degree of media bypass from this design.  Flow
    rates are higher than the eheim models.  Fluvals come with
    included on/off valves and a diffuser bar.  They recently were
    changed to a dark grey/black translucent color with beige hoses.
    Slightly older models are brown/tan with orange hoses.  There is
    no difference between the models except the color.  Fluvals are
    also very quiet, though not absolutely silent like the eheims.  I
    sleep with one 2 feet from the head of my bed and can't hear it at
    night, however.  The hose-attachment clamps are screw-down type
    and can be hard to turn.  They are secure if attached correctly.
    Made in Italy.
 
Magnum:   Magnum recently changed their design from the 200/330 series
    up to the more modern 220/350.  The older models required oiling
    and generated a fair amount of noise compared with the others.
    The new models are magnetic impeller driven just like the fluval
    and eheims.  There is also a new Magnum product called the "HOT"
    magnum (Hang-On-Tank) which I have not evaluated. It appears to be
    a over-the-back filter which has a lower flow rate (250 gals) than
    the bigger magnums, but require no hoses and may be easier to
    set up.  Magnums have traditionally been the cheapest option when
    buying a cannister filter.  Their design has the water entering
    the top of the filter, and being forced through a central
    container from the sides (as compared with bottom to top in the
    fluvals) then to be pumped out the top again.  Magnum filters
    utilize a "cartridge" system which includes  carbon containers and
    micron cartridges.  The micron cartridges can be used with diatom
    powder to provide diatom filtration (see Diatom filters).  The
    filter cartridges are usually covered by a floss sleeve to provide
    coarse mechanical filtration.  Magnum filters provide a high flow
    rate but hold substantially less filtration media than the others.
    Construction is generally considered to be of cheaper materials
    than the other filters, with hoses being held on with rubber
    straps rather than screw down valves for example.  Magnums usually
    are a hot debating point in the cannister filter selection process:
    some people have had wonderful experiences with them and others
    have not been so lucky.  Made in America.
 
 
    Some Functional Information is below.  Numbers taken from
    manufactuers literature.  Keep in mind that flow rates will vary
    depending on what the unit is packed with and how high the water
    must be pumped.  The numbers listed below should be considered the
    maximum possible (they are generally listed with no media in
    place.  Additional backpressure will reduce flow substantially,
    especially on smaller models).
 
 
        GPH   Electric   Manufacturers  Cost (FAMA)
               Usage     Recommended    (US$12/92)   Filtering
              (watts)    Tank Size                    Volume
Eheim
------
2211:   80       5w      <40 gal.        $55            1 L
2213:   116      8w      <65 gal.        $70            3 L
2215:   165      15w     <90 gal.        $110           4 L
2217:   260      20w     <125 gal.       $155           6 L
2250:   380      ??      <265 gal.       $240           ??
2260:   500      ??      <400 gal.       $310           ??
 
Fluval
------
103:    103      7w      <25 gal.        $46            1.18 L
203:    111      7w      <50 gal.        $54            2.22 L
303:    222      15w     <70 gal.        $70            3.70 L
403:    317      22w     <100 gal.       $100           6.48 L
 
Magnum
------
HOT:    250      ??      ??              $58            ??
220     220      ??      ??              $50            ??
350     350      ??      ??              $65            ??
 
 
--------
OLD FAQ:
--------
 
DIATOM FILTERS  (advanced)
     These can be described as purely mechanical filters.  It
relies on the diatomaceous earth (skeletons of tiny animals called
diatoms [di-atom = two atoms/parts]) which "cling" onto dirt and a
 
 
 
-------------------
CORRECTION:  Diatom comes from the Greek: diatomos meaning "cut in
two."
-------------------
 
fine mesh screen to capture the "dirty" diatoms.  Because of the
efficiency, diatom filters are also called water polishers.  These
are not used over long periods (they clog up very quickly), and
hence cannot be considered good biological filters.
 
 
-----------------
Addition:
 
Diatom skeletons are composed of silica and there has been some
speculation as to whether usage in marine aquaiums will lead to "brown
algae" explosions.
 
 
 
 
REVERSE UGF  (advanced)
     This uses the same gravel plate as a regular UGF except that
water is pumped down an uplift tube (in this case a misnomer),
under the plate, and then *UP* through the gravel.  The water
traveling through the uplift tube must be clean, since it would be
very difficult to clean under the gravel plate.  The water can come
from the output of a filter (canister filter for example), or can
come from a new generation of powerheads (submersible centrifugal
water pumps) has a "reverse flow" feature which makes it easier to
use them for reverse flow UGF.  (See POWERHEADS).  The powerhead
should be outfitted with some sort of pre-filter such as a sponge.
     Since the filtration will have been taken care of already, the
 
 
----------
Correction to above:  Since the MECHANICAL filtration will have....
 
 
 
 
 
reverse UGF is primarily a biological filter.  It has the alleged
benefit of keeping fish filth suspended in the water for the
filters to suck up, and thereby reducing required maintenance on
the gravel itself (i.e. dirt does not accumulate in the gravel).
 
 
---------
ADDITION to above paragraph (insert in above):
 
keeping fish filth suspended in the water, or at least not being
sucked down under the UGF plate; allowing for easier removal during
tank maintenance/vacuuming.
 
 
 
 
 
     Because most aquarium equipment was not designed to work in
this manner, one typically has to rig up one's own hose adaptors to
connect the output hose to the uplift tube.
 
--------------
CORRECTION to above:
 
Recently there have been several products designed specifically for
RFUGF use.  Marineland is one company that sells RFUGF units
consisting of powerheads, prefilters and connection tubing.  Other
companies sell reverse flow powerheads, but it is VERY important to
use only systems which have adequate pre-filtration, and not just pump
water under the plates.
 
 
 
 
RO FILTERS  (advanced)
     These purely mechanical filters that are used to purify water
from the tap before introduction into the aquarium.  These devices
use a thin membrane that only allows water molecules (and a few
other smaller dissolved ions) to pass through to the output.  The
unwanted water and materials are redirected to the drain.  This
filtration method wastes water.  RO Filters can also be found at
building supply stores since household drinking water filtration
also uses the same technique.
     There are two common types of RO filters sold.  One uses a
cellulose tri-acetate (CTA) membrane, and the other uses a thin
film composite (TFC) membrane.  The TFC membrane is the best for
aquarium use.
 
 
------------------
ADDITION TO ABOVE:
 
Because the rate of RO water production depends on water pressure,
temperature, and solute concentrations it is important to realize that
unless you have optimal levels of all those above you will probably
only get 50-80% of the production rate advertized.  Drops in
temperature below the 70 degree range usually measured (winter time,
for example) will drastically reduce production.
 
 
 
 

-- 
--------pprior@magnus.acs.ohio-state.edu----(614) 621-8240----------------
Paul A. Prior    Ban anchors, not reef tanks    Nuke Gay Whales for Jesus  
3rd year medical student		        
The Ohio State U. College of Medicine   Tobacco Kills- Please don't smoke!