[Killietalk] RE: Fish room design

["Koran, David HQ02" <David_Koran at hq02.usace.army.mil>]

After seeing everyone else's responses I started to worry I missed Dave's
question on rack spacing--rack spacing versus rows (in rack) distance but
apparently footprint was what he was after.

As for overall rack design let me offer two designs which I have used over
and over again for nearly 30 years.  Back when 2 x 4's were cheap and the
quality was pretty good (i.e., not so many knots and virtually no twisting or
bowing) I found I could make a very sturdy, functional rack with an 8 foot by
20" footprint.  The rack holds 25 10 gallon tanks and setting the top level
at about 3 inches below eye-level and the bottom level 2 heights of a 2x4 off
the floor (i.e., 7") one has plenty of room to work or access the bottom and
middle row of tanks.  The bottom and middle row support are two full length 8
foot 2x4 's set wide side facing out.  Each has 6 cross members (17 " long).
Two in the middle are set 1 3/4 inches from center and two on the end are
recessed 3 1/2 inches, these four supports are also wide side oriented
vertically.  Basically the posts or vertical supports are located in the
middle and on the two ends (6 total) (a 2x4's dimensions are really 1.75
inches x 3.5 inches) and the posts are secured on the inside of the
horizontal frame.  The remaining two crossmembers are located in the middle
of each span and are oriented wide side horizontal (each shelf accommodates 8
tanks, 4 on each span between uprights).  While not the perfect world, what
you have is each ten gallon tank will rest on three sides of the bottom on a
2x4 rail/support.  As for the top row, since you can terminate the upright
post before the top of the rack you can place 9 tanks in the space (figure
10.5 inches per tank in width and you take up 94.5 inches of the 96 inch
span.  I usually notch the upright posts on the 4 end uprights to receive the
top row frame where this "shelf" has the end cross members connected at the
very end of each 8 foot 2x4.  For the top shelf I space 8 cross members at
about 10 and 5/8 th interval centering so these tanks are supported on all
four sides of the tank bottom.  Use 3 inch screws for supporting cross
members to anchor (I was taught in shop class in my early teens that one
screw holds like 5 nails), I use three per union.  As for the upright posts I
anchor each pair to a 20" 2x4 at the bottom of each pair (3 sets) and then
the first or bottom row rests on each of these supports (your bottom shelf
actually is supported by these three cross members).  For added strength (you
will notice that there is your gap spacing between rows on the posts, at this
point I cut a piece of 2x4 to fit between the rows and also anchor these to
the upright posts.  You get an extremely sturdy and rather clean looking
rack.  Remember, if completely filled you have 10 gallons x 8.3 pounds x 25
tanks or 2 tons of water weight.  You can substitute 2x3 cross members on the
non-weight bearing cross members.  You would need 14 2x4's and 3 2x3's or 17
2x4's for the structure and about 100 3" screws and about 50 2 1/2 inch
screws for the project.

I have found that you can also gear this design up and build a rack for 20
gallon tanks with 2x4 construction.  End on spacing of the 20's does make it
a little dicey to get at the back of 20's but you can reach the back the
tanks with a net.  Again, the structure now supports 4 tons of water weight.
2x4 construction allows a 4 tank span without bowing of the shelf on 10's or
even 20's.  You cannot cheat with 2x3's, a 4 tank span of even 10's will bow.
As for spacing between rows if you want to get the bottom row further off the
floor (I remove the bottom 3 cross members and place a "spacer" attached to
each upright to take most of the weight of the bottom shelf) in the instances
where bending is a problem caused mostly by either age or "Dunlap's disease"
(that is where your belly done laps over your belt, ramped in most killie
keepers).  The 8 foot footprint means you shelving can utilize shop lights
for lighting or if anyone is interested I can relate how to split these up,
one tube per 4 to 6' spans.

To cut down on inter-row spacing reduced by the 3 1/2 inches of the 2x4 I
have split them lengthwise and used the 1.75 horizontal front cross piece in
4 vertical row racks but then use a 3 inch wide (or wider) 1/2 inch plywood
spacer support at a mid point of the shelf (the rack is only 5 tanks wide on
the span) which might also work for a 2x3 cross member.

More recently, especially for smaller tanks like 2's or 3's or maybe 5 gallon
tanks I construct a shelf frame out of split 2x4's and "truss" the shelf at
one or more places depending on the span of the shelf by notching out maybe a
half inch on each spanning piece to receive the truss cross member and glue
and then screw the pieces together.  The shelf frame is then covered on top
with a piece of 1/4 inch plywood.  When I connect these to my upright posts
whose structures are 2x4's and each of the shelves rests on a cross member
between the two uprights (your two upright structures end up looking a little
like ladders on the ends) and the shelves are set inside the uprights (you
need a maximum of span on the uprights to limit horizontal swaying!).  The
resulting shelves are light but surprisingly strong.  You can also recess
lighting in the pockets between the truss cross members under the 1/4 inch
top for the next row underneath that shelf.

Unfortunately, not all of us are skilled carpenters or have shop tools
available but consider these suggestions if you do.  I will try to take some
photos if anyone is interested.

Dave Koran
Beaver Construction Division
US Army Corps of Engineers

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