DIY large tank, system plans
Hi:
<Hello there>
I would like to build a tank out of glass and plywood that measures approximately 132" length x 36" deep x 48" high. I have been trying to locate DIY plans for a similar sized tank in the 1000 gallon range, but have been unsuccessful. Do you know where I can find plans, or anyone who will draft custom plans to my specifications?
<Mmm, nope... have seen ads for such plans in hobby magazines over the years... in the back, classifieds... You could easily piece together what's involved from a cursory reading of WWM, other sites... The height is a bit of an issue... I encourage you to consider switching the width dimension... make the system three feet tall, four feet wide... to save on the viewing panel cost, make it easier to work on, in>
I am quite capable of building a tank myself, but I do not have the engineering knowledge required to design such a tank.
Thank you in advance for any assistance you can provide.
Rob Koblasz
<What aspect/s are you wanting input on? Width of materials, modes of construction? Plumbing, filtration? Gear? Bob Fenner> 

Re: DIY plans
Bob:
<Rob>
Thank you for both your time and reply. I guess I have quite a few questions relating to both the materials and the mode of construction. Is it better to use glass or acrylic, and how thick should it be?
<Either might well be preferable in different settings... likely the glass will be less at the shorter height, the acrylic easier to work with (much, much lighter), but scratch and bow more easily...>
As for the plywood, is 1" marine plywood sufficient?
<If braced, screwed every four inches, fiberglass strip and resined in the corners, for the three foot height, yes>
Is steel reinforcement necessary for the dimensions I would like?
<No>
I have an acquaintance with 2000 gallon tank that is 20' in length which was built with steel reinforcement every 2', but I do not know if it is necessary for the tank that I want to build. 
<Not necessary, but advised... especially in an area subject to ground movement...>
I have researched your site and others as you suggest regarding DIY tank projects and I do have a rough idea how to do this. With regard to the height of the tank and the changes you suggest, are there any structural concerns, or just cost and ease of maintenance?
<Quite a few structural concerns... know that for every foot of height such projects about double in cost... in materials>
I believe taller tanks are great for viewing, and floor space might be a concern with the extra foot of width.
<Mmm, I'd do this... make a "cardboard mock-up of the shape/size of the proposed system/s... the three and four foot width/height dimensions, and stand it up in the proposed space... the three foot tall one is very likely the route you want to go...>
I sincerely appreciate any additional information you can provide as I do not want to make a mistake I will regret when the tank is full. It makes for a much happier wife when the water remains in the tank.
Thanks
Rob Koblasz
<I understand this... as well as the (extreme) possibility of the thing coming apart, perhaps killing someone. Bob Fenner> 

Building a large plywood tank 8/9/05
Hello all! I first want to thank you all for all of your time and effort in helping all of the aquarists in need of info. It is so greatly appreciated. Thanks! <Thanks for the kind words!>
Before I start I would like to say that I have read every posting on WWW to do with tank building and construction. (phew, a lot of reading!) I have also scoured Ozreef.com, Garf.com and the internet in general on the subject. <Great!  Lots of good info!>
I would like to build a plywood and acrylic tank with the dimensions of 96" width x 36" depth x 36" height. I was going to use 1" plywood for the frame with a 1" thick acrylic window. The front piece of plywood would frame the acrylic 3" around all sides. I was all set until I went to my lumber yard to get the plywood. After talking to the rep and telling him what I was doing, he informed me that the strength of plywood has more to do with how many layers the plywood has than it does the thickness. He told me that 3/4" plywood with 10 layers would be stronger than 1" plywood with 8 layers. He also told me that hardwood plywood would be stronger than softwood plywood. He had some 3/4 inch birch plywood that was 10 layers.  <Let me begin by saying that I am not an engineer and I have never built a plywood tank (I have built/repaired acrylic and glass tanks).  I should also admit that I am not a fan of the idea of plywood tanks.  If there is any way for water to find it's way to the wood, it will.  Once it does, the wood will swell, fasteners will rust and the problem grows.  IMO, the risk of this is too great to justify what will probably turn out to be a smaller cost savings than it seems.>
1) Could I use the 3/4" birch plywood or should I stick with my original plan and use 1" exterior grade plywood? If I go with 1" plywood, could I get the same strength by gluing two 1/2 inch pieces of plywood together. (My lumber rep tells me that the glue bond would be stronger than the plywood itself) <Your lumber rep is probably right... the strength of the plywood probably has more to do with more layers than absolute thickness (within reason), but also has a lot to do with the type of wood and the type of glues used.  These types of questions should really be directed to a structural engineer.  In any case, I would definitely use dimensional lumber ribs/spines to add strength and rigidity to the plywood and coat the entire structure in a marine grade epoxy or fiberglass after proper surface prep and priming (do you see the costs mounting?<g>)>
2) Is the 3" border for the front frame enough to hold the acrylic viewing pane in place or should I make it 4"?  <I would guess that 3" is enough, but not if it is made of unsupported plywood. Even if the border is well secured to the adjacent bottom or side panel, it will support relatively little pressure, especially if it gets wet.  I would want at least the bottom perimeter to be supported by dimensional lumber (wide side down, so it couldn't "roll") that was anchored to the same sheet of material that formed the bottom of the tank.  This would prevent the sides from being able to "blow out".>
3) Instead of using plywood top braces (which would block some of the light going into the tank), could I use 1" thick acrylic braces that would be drilled and screwed to the plywood frame? How wide would you make the top braces?  <Tropicorium in Michigan uses wooden tanks in their greenhouses.  They support the tops with steel cables or threaded bar covered in garden hose to protect it from the water.  This is very strong and block almost no light.  Drilling and screwing through acrylic is risky because acrylic is "Notch Sensitive".  Think of scotch tape... it is very strong if you pull on it, but if you nick the edge, it tears very easily.  Small holes drilled in acrylic act like the nick in the edge of the tape.>
4) I actually plan on making the tank 37" high. The extra inch will be on top to accommodate the 1" thick top braces. (nestled in between the front and back walls)  The water column will still only be 36" though. Is this ok? <Yes, but calculations should be based on the depth of the water.>
5) Instead of coating the inside plywood with resin or epoxy, I was thinking of using thin acrylic sheets (1/8") to cover the bottom, sides and back. I figured once I had the front  1" acrylic viewing panel siliconed to the front, I could use the thinner acrylic and  bond it to the front piece and then bond all the other acrylic pieces together. This in effect would create an acrylic box inside of the plywood box.  <This is a great idea, but you would still have to coat the plywood to protect it from moisture (even if it is protected from frank water contact).  Also, if moisture did swell/warp the plywood, it would easily crack the thin material allowing gross water contact. All this brings us back to the issue of cost.  I suspect that if you add up all of the costs of the acrylic, plywood, acrylic adhesives, etc. that your savings would start to shrink.>
6) Is the 1" thick acrylic enough for the front panel? Can I go thinner? Should I go thicker? Thanks so much for your help.    Mike <1" is thick enough if it is adequately supported.  A couple of cross braces should do it if the top edge is beefy enough (I would think 4x4 lumber or maybe even angle iron).  www.cyro.com has a thickness calculator that you can use.  Sorry for my pessimism for your project, but spending the money on a tank built by professionals is cheap insurance against 450 gallons of water on your floor and a tank full of dead animals.  If you do give it a whirl, good luck!  AdamC.>

Even 300 Gallons Can Be "Small" - 08/22/05
Yes, I know. The Yellow and the Naso were rescues from a poor vendor in Toronto.  I am surprised how well they have done.
<<me too>>
My fiancée and I are building a new house and we are incorporating an Aquarium room.
<<sweet!>>
I am having a 300 gallon acrylic tank made for one wall by a company in Minnesota.
<<Getting closer.>>
It will be the main display reef and I am thinking of using the 180 as a seahorse and kelp setup.
<<Very nice.>>
I don’t think the tangs will grow too much in the next 9 months.
<<No...likely due to developmental retardation...>>
Thanks again.
Ps. Do you know of anyone who has made a reef out of a swimming pool? I thought this could be a nice project to have a 20000 gallon system under a greenhouse so that one could swim with the display.        
<<Have heard of such, more recently a new construction discussed on RC...and once saw pics of a 7,000 gallon outdoor "lagoon" system with a giant viewing window in the basement(?) wall of a home in Hawaii...fabulous!  Regards, EricR>>