Tank Reinforcement 10/3/08
I have a 225 gallon homemade tank. It is 6 feet long 24 inches wide and 30 inches high. The glass is 14mm thick. The seals between the glass panels don't look too good. There are a lot of bubbles and some gaps that go almost all the way across the thickness of the glass.
<Not good.>
There is no center support on the top on the tank. Can I silicone a strip of glass (1/2in x1/2in x length of seam) in all the corners to reinforce all the seams.
<While you could silicone glass at each joint, ½” strips just will not do the trick. Given the sound of these joints I would just disassemble the tank, thoroughly clean off all the old silicone and start over. This is a ton of work, but it is the only “right way”. Re-dos and time is the price we sometimes pay for DIY! Some bubbles in the seam are normal, but many (especially the larger ones) will spell disaster. If you have never tackled a project like this before I highly suggest either practicing first on a smaller scale or employing the help of somebody with experience. Do also be sure that the glass is fit well together; do not leave a small gap for the silicone. This is a common mistake, this gap will only weaken the joint and allow the air bubbles.>
I read what you said about adding a center support.
<I would definitely add the center support for a DIY tank of this size. Good luck, Scott V.>

Tempered bottoms, glass tank manuf. choice  11/23/08
Hello,
<Dave>
After buying an Oceanic Tech 120 gallons and returning it 5 times (that's right 5) because of various problems including 2 that arrived cracked....I give up on Oceanic...their quality control is non-existent...I decided to get essentially the same tank but made by a local custom tank manufacturer.
<Used to be a good co.>
Now i have the option of a 3/4 inch non-tempered bottom just like the Oceanic tank had, or a 1/2 inch tempered.
I'm not planning any drilling...which is the way to go?
<... "Six of one...">
Seems to be some disagreement on what's better, though I notice that manufacturers making "higher end" aquariums tend to specifically state that they use non-tempered as if it is superior. Can you offer some advice?
Thanks,
Dave
<I'd likely go the 3/4 inch bottom route... as someone may at some point decide to drill it... these two choices are fine, near equivalents in terms of strength... the 3/4" inch being a few tens of pounds heavier to lift...
Bob Fenner>

Eurobracing 72"L x 30"W x 29"H glass only tank 5/21/08
I have glued together a 72"x30"x29" glass only tank with silicone (1/2" thickness). Bottom pane tempered, all remaining glass resting on top of the bottom plate, non-tempered.
<Good thickness and design.>
I put in glass bracing on the interior bottom perimeter of the tank 3.5" x 1/2" siliconed. The next question I have regarding this process is the nature of the top bracing. I was planning on Eurobracing and also adding a 29" x 12" (1/2" thickness) center brace underneath the Eurobracing.
<This would give you the ultimate combination of support along the top.>
I was then advised that another possibility might be to install an exterior perimeter using brushed nickel channel mitered and then screwed together at the corners that would have a better finished look and be stronger than the Eurobracing or center brace (interior).
<Hmmm, this can work, you will still need to have cross braces with this material, it will still bow. As for strength, you will not beat the glass cross brace.>
Cost is similar (likely glass a little cheaper). It was indicated that brushed nickel (aluminum) would not corrode when subjected to an exterior salt water environment (salt spray).
<Aluminum will corrode with saltwater, the two do not mix well. Many believe it does not corrode because it does not look like the ferric rust that we have all seen.>
What are your thoughts regarding which of these methods would be the best course of action (assuming pricing nearly the same)- providing strength, preventing bowing, and corrosion?
<It is much easier (and superior IMO) to use the glass bracing. Given the tank dimensions and glass thickness, either the Eurobracing or a few cross braces will work. Using both will give you that much a stronger tank.>
Mike Cox
<Have fun, Scott V.>

Re: Eurobracing 72"L x 30"W x 29"H glass only tank 5/23/08
Thank you for the quick response. Just the expert opinion I was looking for. I will proceed with Eurobracing and center cross support.
<Welcome, this will be a very sound tank! Enjoy, Scott V.>

Aquarium Building 03/28/2008
Hi,
<<Hello, Andrew here>>
I am trying to make an aquarium and the dimensions will be 72"L x 16"H x 24"W. I was wondering what glass thickness you recommend?
<<Please use the following glass thickness calculator http://saltaquarium.about.com/cs/aquariumdiy/l/blcustomtank.htm >>
Thanks
<<Thanks and regards. A Nixon>>

Tank Building Beginner 3/22/08
Hi all,
<Hi Brian.>
I've read a lot on your site, and it is pretty informative! Great Job and thank you!
<Thank you, we are happy you find it of good use!>
I want to build a tank 48x18x15. I have never built a tank before and I have lots of questions I am having trouble answering. I'll itemize then for you:
1.) I have several 1/4" plates from an old store front, 54x45, it's clean with no major scratches. Is this suitable for building a tank?
<Technically, yes. I would opt to go a bit thicker for a DIY project of this size. Overbuilding is one advantage of doing it yourself.>
2.) If there is a small bubble (size of a pinhole) in the glass is it no good?
<This can be fine, but do keep in mind that the ¼” glass is already at the bare minimum for this project strength wise.>
3.) Is there a difference between 100% silicone and 100% RTV Silicone?
<There is not a difference so long as the RTV has no other additives, some do some don’t.>
4.) Are all 100% silicone's created equal, or do you have a suggestion on a brand or something to look for?
<100% is 100%. Do be aware that some are not 100% silicone, they contain mildewcides and other additives to prevent mold growth. Stay away from these.>
5.) Is there an difference between 100% silicone and Aquarium Sealant, beyond the packaging?
<Nope.>
6.) How perfect do the cuts in the glass need to be for success?
<Fairly straight and square.>
I've been practicing cutting, and find that there is occasionally a slight taper in the edge, or minor rippling along the cut, it that no good?
<This is not good, especially when you consider only a ¼” bonding area. You want a good glass to glass fit with a minimal amount of silicone between the pieces. The silicone should not be used as a gap filler.>
Well I think that’s a start, and thank you for your help guys!
Cheers,
Ben O'Brien
Maine
<Welcome, Scott V., central California.>

Glass Thickness 2/15/08
Hi Guys
I have tried to work this one out, but I want to run it by you as I am a bit lost. I am going to get a 130cm L x 80cm W x 80cm H tank made.
<Approx. 51”x31.5”x31.5”>
I am debating normal or eurobracing.
If I go with normal bracing (with one central and two side bridges and the normal full length supports front and back), is 15mm glass thick enough?
<It is technically enough, but I would still opt for thicker glass for this height, it is better to overbuild with this volume of water in your home.>
If I go with eurobracing (top and base of the tank), will 19mm be the right thickness. Some friends said this glass is too thick to make my tank with. What is your opinion?
<I think this is a fine option; the glass is not too thick. I love the Oceanic Tech (and other) series tanks for one reason: they use thicker glass than is necessary. You can go with the thinner glass, but the thicker option will give you piece of mind and be far better with the Eurobracing. Do be sure your Eurobrace strips are fairly wide, like 4” (10cm) plus.>
Many thanks
Brett
< Welcome, I will ask for Bob to input also. Have fun, Scott V.> <<I am in complete agreement with your statements. RMF>>

Plastic Frame Supplier   10/2/07
Do you know where may I purchase injection molded plastic tank frames for aquariums (10 gal, 20 gal, 30 gal, etc...)
Thanks,
Fernando Marino
www.acuariosmundomarino.com
Monterrey, Mexico
<I would contact the major manufacturers of glass aquariums in the U.S. re: Oceanic, Perfecto, All-Glass... they may well be willing to sell you. Cheers, Bob Fenner>

Glass tank... frames? DIY const. 10/26/07
I seem to be finding conflicting information everywhere I look (including differing opinions on this site) on this subject.
When building a glass aquarium, do frames around the top and bottom of the tank help or improve strength?
<My answer (there is a lot of conflicting opinions out there) would be, are you ready, it depends. Wow, really informative, eh. On smaller tanks the frames do four things. First, they provide a simple way to hold the panes of glass in place as the silicone cures. Second, they protect people from sharp edges when lifting the tank and feeding. Third they protect the tanks from banging into each other during shipping and display, and to some extent accidents such as dropping or setting it down roughly. Fourth, they just look more like a finished product. On some medium to large tanks they can be structural, to prevent deflection (bowing) of the longer panes of glass. This is usually done with a center brace incorporated into the frame, which might even appear relaxed and loose without water in the tank. Some of the larger tanks will just use a piece of glass across the middle to fight the deflection.>
I've also seen pictures of "frameless" tanks that instead have a 1" or so strip of glass around the inside perimeter of the tank, about an inch
or so from the top.. Does this do or help anything?
<This is the “hot” way to brace the tank against deflection (aka euro-bracing). The continuous strip of glass minimizes bowing and keeps the middle open for access and lighting. In larger tanks you will see more than a 1” strip.>
Thanks!
-Mike
<Thank you, Scott V.>

Glass question  – 10/24/07
Hi,
I recently acquired around 10 large panes of 1/4" glass that I'm pretty sure were used on desks/tables.. If there are no major scratches (that I can't work around), would these be suitable for aquarium construction? I know 1/4" limits me to 12 - 18 inches high depending on which site I'm looking at.. A couple chips on the edges tell me it's not tempered..?
I've been wanting to build something around 36" to 48" long, 15" - 18" high, and about 18" front to back.. How am I looking?
Thanks for the great site!
-Mike
<Mike, not a great idea. Aquaria are built with glass designed to hold the weight of water and more important resist accidental bumps without exploding. At least here in the UK, and I guess most other places, there are specific standards aquarium manufacturers must adhere to when selecting glass. Composition, thickness, etc all come into play. It's sort of similar to the standards motor car manufacturers must follow when choosing glass for the windscreens on their vehicles. As much fun as DIY might be, the risk here is, in my opinion, too great. Do this wrong and the tank could explode, sending fragments of glass all over the place, as well as (obviously) killing any livestock. By all means use the glass to build a habitat for terrestrial reptiles or for some interesting ferns or something, but skip the fish tank idea. It's not as if you're likely to save much money either. The glass aquarium is usually a pretty cheap part of the whole system compared with the hood, stand, lighting, etc. Cheers, Neale>

Large DIY aquarium, glass thickness for a five foot tall...   7/26/07
Hi, Thanks in advance for taking the time to read this question. I'm looking at building a large aquarium based on the designs on this website http://www.cichlid-forum.com/articles/diy_1700g_tank_1.php. The dimensions of the aquarium will be 6ftX4ftX5ft high, with a viewing window of 5ftX4ft. I know tall aquariums are not your favorite design, but since the aquarium will be floor standing it should take out some of the maintenance head ache. I'll get some go go gadget arms installed later J, I currently have a 36" tall aquarium on a tall cabinet which stands at about 6ft in total so I know what I'm getting into.
<Ah, good>
I have
found a local glass supplier who recommends 20mm toughened glass. With your experience do you think this would be suitable for such a project?
Thanks Again, Michael
<Mmm, no... not near... I would not build this height with anything less than 31.75 mm. (1 1/4") glass of this nature. Bob Fenner>

Re: Large DIY aquarium  7/27/07
Thank you for such a quick response. One other small question would you recommend the 31.75mm glass was toughened?
<Yes... I would use the best glass (e.g. Starphire by PPG brand) you could afford... not float, nor tempered>
I have heard mixed reports of using toughened glass on aquariums. Due to the extra weight I may decide to get a sheet of acrylic what thickness would you recommend?
<... For acrylic in these proposed dimensions, the equivalent of an inch and a half, to reduce bowing. BobF>
Cheers
Michael

Double Pane... laminated glass use  - 02/20/06
Dear Crew
<TB>
I was recently at a local shopping mall that has a number of large aquariums on display. One such aquarium is fairly tall ( I would be
inclined to judge it at over 1.2m in height). I was fortunate to observe the maintenance crew working on it at which time I also noticed that it
used fairly thin (approx. 8mm) glass, but that these were double - that is to say, each side of the aquarium was made up of two 8mm pieces of
glass placed flush against each other giving a thickness of 16mm glass.
<Yes>
I am writing to enquire whether you had any information regarding the strength of such a setup, given the considerable price differences
between 8mm and 16mm glass. Presumably this will ensure better insulation, but will it be as strong as 16mm glass?
<Can be considerable... is "laminated" for increased strength>
Also, would it then not be a good idea to use standard glass on the inside, to contain the water, but toughened glass on the outside.
<Mmm, no... not the purpose in this case. A related use of "two panes" is their employment in public aquarium settings... where the "outside" piece is easily scratched (by diamond rings etc.), leaving the inside to work functionally... with a desiccant of some sort in-between to discount condensation>
This would offer the desirable breaking properties of normal glass (in case a small crack should develop) with the toughness of toughened glass?
<Mmm, no... Look up the term "Starphire glass" on the Net>
Thank you for any feedback.
Gratefully,
Tim
<Bob Fenner>

Re: Double Pane  - 2/21/2006
Dear Bob,
<Tim>
I would thank you for your email but for the fact that I now have yet another reason to feel unsatisfied with my current tank - I want Starphire glass!
<Heeee! Is gorgeous... clearer than most all... sparkles>
Surely a tank that has everything including a small price tag and that can hold any and all fish, corals, inverts and other things (living or not) that I can throw at it in perfect equilibrium is not too much to ask for! :o)
Have a great day!
Tim
P.S. I would love to help answer questions - I have read to the point were I feel confident answering all but the most unusual questions! Unconvinced? Ask me...! How can I get involved?
<! Do you have time? Expertise? Obvious to me you care and are proficient in written English. Please do join us. Bob Fenner>

Silastic bead input   3/4/06
This is a follow up to a reader post on his construction of a 300 gallon glass tank with MDF base with fiber glass sheathing. Re: Tank Fabrication   3/3/06 . This is my third posting in a week (I will try not to make a habit of this). I thought my experience may be of some interest and help.
<Thank you for this>
The reader had some trouble with bubbles in the seams. I have seen this in a lot of tanks. Most of the time you can get away with that as silicon holds 300 lbs per square inch. Common practice is just to fit the glass edges together in a similar fashion to working with wood or acrylic. This results in a silicone seal that is not thick enough, and the risk of bubble formation later. I read the directions on a tube of silicone sealant ( Silaflex RTV), and it states…
Extrude sealant into joint. Minimum joint size 5 mm wide x 5 mm deep and maximum joint size 25 mm wide x 10 mm deep
One of the glass and window suppliers here in town went on a conference and one of the topics was how to silicone glass together. He was told the depth of the seam should be about half the thickness of the glass. So a 10 mm glass should have a 5 mm deep seal. This offers a stronger and more flexible seal, and less chance of bubbles.
I have built about 3 all glass and 3 glass/plywood tanks and I have never got any bubbles in the seals doing it this way. Vertical glass panels can be held in place when gluing by cross bracing the corners with strips plywood that has two sided foam adhesive tape on it, and simply pressing them on the top edges, and easily removed later.
Commonly the side panels of the glass are laid on top of the glass base. It may be a better approach to lay the vertical glass panels around the base and allow for a large seal around the edge.
I always pay extra to have the glass flat polished with smooth bevels on the edges. It is safer to work with, and I think essential on tempered glass, as a chip in an edge can cause the panel to explode.
Have Fun
Mike Lomb
<Thank you for this Mike. We have some trouble with some "tray less" queries (yours here is one) that don't have email addresses to respond to... but am hopeful you will find this posted in the dailies, and that others will benefit from your input passed on. Bob Fenner>

Glass Thickness Information
Hi Scott F
<Hi there!>
I think I found the glass thickness article you were trying to think of. It is from New Zealand (who would have thought it! (little bit of Australia vs. New Zealand rivalry is always fun :p (I'm an ozzie BTW))).
<Oops...my "Seppo" ignorance strikes again...!Well- at least I was in the right hemisphere! LOL>
The article is EXCELLENT. It has comprehensive explanations and equations and for those that are lazy they can just download a spreadsheet to do it all for them. The address is:
http://www.fnzas.org.nz/glassthickness.0.html
Cheers, Adam L
<Yep- that's the one! Thanks so much for sharing it with our readers! Regards, Scott F>

DIY Glass Tanks
Bob I am new to your site and have looked through several of the FAQs but do not know where to post a question that you might be able to answer.  So I hope you do not mind the email.  If there is an appropriate place on your forums to post this please let me know.
<Hey Stuart, you've got Gage today.  Feel free to shoot us emails with questions, there is a ton of info archived in our FAQs and many knowledgeable folks on our forums as well http://wetwebfotos.com/talk/  >
I am interested in building a large tank, 94 by 36 by 48 inches high. Preferably out of glass.
<Never done it myself, I am considering plywood and glass myself, GARF does not recommend making the tank taller than 36inches.>
I am having trouble with the glass requirements.  Different tank builders have told me different specs, and I do not know which is needed.  One whom I am not sure I trust would uses standard ¾ inch glass.  2 others whose prices were in the stratosphere said they would use ¾ tempered glass..
<Error on the thicker heavier side.  From what I understand you cannot drill tempered glass, are you going to want drilled overflows?>
So my question is; making the tank out of glass, with additional ¾ by 2inch gluing doublers, is ¾ inch glass adequate, or is tempered glass or thicker float glass needed?  3 top braces are planned.   If so would an additional steel frame around the tank be required?
<Let me give you some links to some people who have more experience with this than myself.
http://www.garf.org/
http://www.ozreef.org/diy/index.html#TANK  >
Thank you for your time.  Any additional recommendations are welcome (I know don’t build it yourself :-) )  Thank you, Stuart
<No way, Go for it!  Just be sure to test outside, thoroughly.  A carpet cleaner with good extraction power is always handy.  Best Regards, Gage>

Glass Thickness Usage...
Hi,
Ok maybe this will help, it seems mm to inches may not be helping us here. Glass thickness 10mm = 6/16ths (remeasured in imperial) 7/16ths is 12mm from what I can figure.  I had wanted to use 12mm but it was very expensive and hard to source.
<Okay>
I have previously had (from the same glass 10mm (6/16ths)) a tank which measured 72 inches by 24 inches by 24 inches, (or 1830mm x 610 x 610mm) this tank had a 10mm strip right round which sat on top of the glass with a crosspiece across the middle to prevent bowing, it was full to within 2 inches of the top.  Tank now sold due to relocation issues.  I have not planned a crosspiece for this new aquarium.
<I would>
Hence it was on this which I based 50mm extra height minus 600mm length should be a significant reduction in stress over length therefore it should be fine (well that was my reasoning / guesswork). The tank is therefore in inches 26 inches high at the rim and 47 1/4 inches in length.
<I would still brace it... front to back>
I have an equation for calculating to various dimensions however I can't drive it (I sucked at physics) http://www.fnzas.org.nz/glassthickness.0.html that link takes you to it should you find it interesting. I would be very curious to know the safety factor on the current plan.
<Yes... very interesting>
I take it by <much better> you are referring to the Dow Corning 1080. It may (still hasn't arrived days late) be neutral cure as they got the wrong one in (white) earlier in the week which is neutral cure. I've yet to decide on what species and how many algae feeders I will need (the tank will be brightly lit without CO2 injection but with potted plants e.g. Java Fern (no pot) and Vallisneria plus whatever else I can get which will handle hard water ph 8.2.
Any suggestions on species for algae (many fish are unavailable here) feeders?
<My opinions on such are posted on WetWebMedia.com, under the freshwater subweb (linked on the homepage)... you can follow the index from there>
I've still to decide on additional species of cichlid & the total number of fishes the tank will support.
Current 3 foot tank (1 foot wide) has 7 fish.
Filtration:  2 canister filters doing 1000 liters per hour each.  
Media at this time unknown but bio mechanical, chemical e.g. carbon or similar.
Possibly an air stone but undecided.
Fish stock on average 6 inches in length. I've heard 1 inch of fish per foot of surface area but... that theory allows for 1 or 2 fish only which is not applicable for a 400 liter tank.
I want to go to 80% of maximum capacity for stock.
<Less is better as the saying goes>
Plan B on the log retrieval cutting gear is going to cost me $300 per hour which is way excessive.  I will likely find something dead & sink it in a lake to 100m depth to saturate or use baking soda or both.
<You might look about for artificial or real submersed wood... such is sold (like "Mopani" wood out of Africa) in the interest>
Dunno it depends on what I find when I re-dive the log jam.  Hand saw will jam & be a pox to drive in a current (its in a river).
Gotta go to work
<Very interesting project indeed>
Thank you so much for your help thus far.
Cheers
Jim.
<Thank you. Bob Fenner>

Aquarium of size 14ft x 3.5ft x 5ft
Hi,
I am Meeta Rao for Mumbai - India. I want to build an aquarium of size - length 14ft x width 3.5ft x height 5ft. I want to know what thickness of glass will be required to make this aquarium. Also approximately how much it will cost in US$. Since this is going to be a marine aquarium, if you could please tell me what kind of filtration would be required for this aquarium.
Waiting for your reply.
Thanks
Meeta.
<There are a few ways to build such a size system (different materials like block, metal-frame, acrylic... glass viewing panels...) with varying costs, need for specialty help. Do you want to be able to see into all four sides? Or just one? Is this to be a permanent install or do you want to be able to move it at some point? If money is no object, I would have it fabricated out of acrylic... about 1 1/2" thickness all the way around (including a top with cut outs for access). Much to be said re your possibilities for filtration. What sorts of life do you intend to keep? What is your background in the hobby? Bob Fenner>

Re: To brace or not to brace, actually to use or not to use
Hi Bob
<Chris>
Thought I'd do this as a reply to your last email, rather than a new email, so you can see the texts of our previous exchanges.
<Okay>
Well, as of this evening, tank construction has finally begun. But problems have emerged, and I would really value your advice.
I have used this glass supplier for a number of projects, but never for aquarium glass. I've always found their cutting accurate, and therefore this time I just quickly checked for overall dimensions, not for right angles on faces or edges.
MISTAKE!
A number of the glass edges are not at right angles to the face, and two of the sheets - a side and a front - are not perfectly rectangular. This means that the front glass - the final piece, and therefore the one where the mistakes accumulated - has masses of air bubbles in the silicon seal which I could not eliminate - even when banging pretty hard with a rubber hammer.
<... not good>
Where some of these bubbles reach the outside of the seam - inside and/or outside the tank - I intend to run more silicon into the gaps tomorrow. But numerous bubbles will undoubtedly remain. How disastrous is this? And if you think it is disastrous, what can I do about it?
<Can be real trouble... the only real strength in these constructs is the silicone between the glass to glass surface area... less of this area, or more gap between the sheets, bubbles... equals less strength.
And just for future reference, was I wrong to keep my bead of silicon to 1/4 inch for 1/2 inch glass? Should my bead of silicon have been of the same thickness as the glass (1/2 inch)?
<Mmm, nope to all... as stated, the real strength of these joints is just a smear of silicone... the rest of the material is to protect, more or less, cutting into this area (between the glass sheets). Some tank manufacturers in Europe like Juwel, actually leave off any "extra" silicone... and folks who know how to use silicone really well, can make a whole bunch of tanks whereas sloppy folks (like myself) don't get near as much per volume of silicone>
At the back left of the tank, where the side piece of glass is not perfectly rectangular, the gap at the bottom is 3 mm (1/8 inch), but that can be filled with silicon. Again, how disastrous is that?
<Can be tremendous... I encourage you to make the current tank into a terrarium... or a snake et al. enclosure... really... and start over with panels that will leave NO gaps>
And just to end my tale of woe, the left side piece is 4 Mmm (3/16 inch) above the top edge of the back glass, and the right side piece is 3mm above the top edge of the back glass. Which means that if I run my bracing strip along the top edge of the glass (as we discussed earlier), there would be a 3-4 mm silicon-filled gap between the bracing strip and the top edge of the back glass. Any thoughts on this?
<This is not so much of a big deal... and some more bracing can be cut, fit, siliconed to fit inside and attached to this "on top" bracing if so desired. HOWEVER, I would NOT use this tank with the gaps stated as a water-filled container. Sorry to be the bearer of bad news. Bob Fenner>
Thanks in advance for your help,
Chris

DIY 180 all glass tank 72X24X24
I am considering building an all glass tank 72x24x24.  I have a relative in the glass business with access to automated cutting equip, drilling, sanding, tempering, etc.  
<Great>
I don't think he personally knows much about the aquarium industry because they don't specialize in that.
<Many uses, subspecialties>
  However, based on the above info., I think I can get a good deal on glass.   It would cost no more for tempered glass vs. plate glass.  If I decided to have it drilled, he could do that before tempering.  My questions:  Is it advisable to do an all tempered glass aquarium instead of an all plate glass?
<Mmm, not necessarily>
If all tempered is o.k., then could I go 3/8" tempered glass instead of 1/2" plate since it is 10x stronger?  Is it safe to use 3/8" plate glass on 180 gallon?
<The 3/8 tempered would do, especially if you're building a frame to set it all in, but if it were me, mine, I'd go with the 1/2"... likely no more expensive, and will bow much less>
Would the answer to any of these questions change, and if so how, if the tank dimensions were changed to 72X30X24 (L X W X H)-225 GALLON? I have heard, if you exceed 30" in H and/or W that it requires special engineering.  What is your take on that question?
<Theoretically the width is structurally unimportant... as long as the bottom is supported evenly (perhaps a bit of foam sheet over a piece of ply, supported underneath... Only height increases stress on the glass. Bob Fenner>

Re: DIY 180 all glass tank 72X24X24
Thank you very much for taking the time on these questions.   A couple of follow-up questions:
If it were you, would you go fully tempered 1/2" tempered tank or fully 1/2" plate glass tank, or some other combination?
<If the same price, take the tempered for sure>
Is Starphire glass or lamination significantly any better visually viewing tank inhabitants than tempered or plate glass?
<Yes, it is>
Is tempered vs. plate significantly any worse visually viewing tank inhabitants?
<Virtually no difference>
Lastly, for a beginner like myself, would you recommend constructing a tank of the dimensions listed, or is it simply too risky?
<Not very risky... but might get some help with your first try at siliconing... or practice making a smaller tank/sump, or two... build the top (sides, front, back) on top of the bottom... use either wood working clamps or substantial strength tape to hold the pieces together, taking apart, doing one joint at a time, re-securing it with clamps/tape... allow to set for a day, invert and re-square with the bottom, have some friends help you lift the bottom for the bead there... allow to set... run a bead along the entire inner seams. Bob Fenner>

Re: DIY 180 all glass tank 72X24X24
I'm sorry about the over-kill, but I want to get this right.  Let me read back to you what I think you are saying with the construction.  The final tank will have all plates resting on top of the bottom plate.  The ends will be on top of the bottom plate in between the front & back plates.
Step 1: silicone- "joint" is where the bottom edges of (Front, Back, Side) plates touch the bottom plate & the end plate edges touch the ends of each side of the front/back plate- let cure.  Step 2: silicone "joints" -the bottom plate to the previously siliconed front, back, side plates-let cure. Step 3: run a bead of silicone to all interior 90 deg angles where glass meets, running finger along in one continuous motion to smooth into corners-
<Or a tongue-depressor, popsicle stick... and then after curing (a day or so) trim off the excess with single-edge razors>
let cure for 48hrs before water test.  In other words, there is silicone on all glass surfaces where glass meets glass.  Would you recommend putting 2" strips of glass all around the top edges (not resting on top, but within the tank)  AND/OR  2  6" pieces of glass 1/3 of the way in from each side, connected to front & back panes for support?
<Yes... even if building and setting the tank within some sort of frame. Bob Fenner>

Re: DIY 180 all glass tank 72X24X24
Thanks for spending so much time with me on this.  I tend to be a little retentive, but I don't want this blowing out all over my floor. Thanks
again!!
<Glad to help. Bob Fenner>

Building  a large glass tank
I am planning to build a 180 gallon glass aquarium. <Hey Mike, MacL here with you today.> I am new to the hobby and have tried to read as much as I can on water circulation/overflows. <Very smart.> I plan to do FOWLR, but would like to plan for the eventuality of going
reef.  There is a lot of articles discouraging the use of hang on overflows. <I think that's because many of the overflows have problems.> I have read a little on Durso overflows, horizontal overflows, some of the DIY overflow designs.  It has all become a little confusing. <I can see where that would be.>
In your experience/opinion, what are the best options for high flow, and as silent as possible overflows. <Personally I would drill the tank for optimum overflow and I'll be honest and tell you that my first tank originally was set up with a corner overflow and I will NEVER do that again.  I have ended up with a lot of detritus that I cannot get to clean it up in the overflow and I hate it. My newest tank will have the holes drilled into the main part of the tank and on the back. Let me know what you decide and if you have any more questions. MacL>

Aquarium Bracing
Hi there
<Hello>
I have read articles on your site regarding the "Euro-style bracing" and have decided to do the following.
The aquarium is about 41"L x 36"W x 30" t.
<Mmm, a bit tall...>
I am planning on putting the braces in about 1" from the top.  The braces are about 3" wide (10mm thick).
Can the front brace be, say 2" for easier tank maintenance.
<Mmm, I would make it at least three inches wide/thick for 3/8" thick glass, this height of a glass system>
Now the other thing I was con fused about was where the braces go? ( yes I no they go in the tank)
If I first attach the front and back brace 1" from the top, then do the two side braces go on top of the front and back brace, so at the corners the thickness of glass would be 20mm?
or
Does the bracing all sit flush?
<The former... they should overlap... with them overlapping, touching at the corners, faces>
can you give me a link or tell me the easiest way to attach the braces?
(stands, clamps, tilt the tank?)
<Maybe look on Ozreef.org>
I think you guys and girls do a great job, this site would have to have some of the best content, regarding aquarium life etc on the net.
Keep it up
Regards
Tim
NEW ZEALAND ( no we are not part of Australia)
<Heeee, the Land of the Long White Cloud? Not hardly. Bob Fenner, who has been to Rotorua... stinky air, great folks and beer>

Aquarium gluing procedure
Greetings Crew!
<Hello there>
Say, here are your stupid questions for the day... I am ready to assemble a 130 gallon aquarium. The pieces are made of 1/2" thick float glass, and the largest weigh 60 lbs or so. The front, back, and sides of the aquarium sit on top of the base glass. So, the weight of the glass will squeeze out all but a thin layer of silicone when the assembly takes place.
<Sounds good thus far>
Some people use shims during the aquarium assembly process, and then remove them at various stages of the process. Question, would you use shims?
<Nope... good strapping tape (the stuff with the fiber in it) and wood clamps are my fave instruments with this size of construct>
And, if so, what thickness, material, and quantity? Finally, are the shims removed after the silicone is set, and the resulting gap filled?? Or, are they left in place?
<No shims, please... the barest amount of Silastic left in place is all you want/need... let all set up on the outside for a day before trimming (single edge razor blades) and gingerly lay in a bead on the inside edges (after tape, clamps) in all inside joints. Bob Fenner>
Please sign me, 
Haven't got a shim
(James Bradley) 

DIY Glass Tank
I am planning to build a glass aquarium 72"x30"x24". I was wondering if you have any suggestions on the following questions: When having the glass cut to the above dimensions, should any adjustments be made for the space that silicone will take up between glass surfaces?
<Mmm, no... but the width of the glass needs to be considered... if fitting the ends inside the front, back panels... I take it you will build these onto the bottom>
If I had all edges beveled, seal surface area might be reduced on bottom edges...would there be any consequences to losing the seal, strength, or leakage by doing this?
<Yes... only bevel the tank after it's assembled. Practical warning here... be very careful of glass cuts... easy to do...>
Any suggestions on how to minimize chance of bubbles in seal other than just buying a ready made tank?
<Practice on a smaller system first... perhaps a ten or twenty gallon... that you can use for other purposes...>
Thanks again for your many valuable insights!!!
<Glad to share. Bob Fenner>

Re: DIY Glass tank
Yes, I do plan to place all panels on top of bottom panel. I also plan to put end panels in between front and back panel. My brother who is in the glass business will be cutting the glass (I think he said it could be done by computer) and beveling. I think he can bevel before assembly, which should decrease chance of cuts during assembly.
<I'm not being clear I guess... You do NOT want to bevel the edges until the siliconing is done... you want to maximize the surface area/contact of the glass... Just bevel the outside edges (after the tank is sealed>
Should I make the bottom plate 30 1/16" wide so that the end panels do not push the front & back panels over the bottom panel edge after silicone applied? 
<What? No... the amount of silicone is miniscule... no need to allow for a gap>
I guess I could alternately make the end panels just 28 15/16" (using 1/2" glass)? Do you think 1/16" is enough space to accommodate the silicone?
<Bob Fenner>

Tank Design 7/9/05
Bob:
<Ben>
The following was the product of a "tank calculator" on the GARF.ORG website:
"Tank Information:
     Material = Glass
        Tank Height = 30"
        Tank Width = 36"
        Tank Length = 72 "
        Glass Thickness = 1/2"
        Approximate Gallons = 337
<From the outside dimensions>
Cut List:
     Bottom = 71 " x 35"
        Front = 72 " x 30"
        Back = 72 " x 30"
        2 Sides = 30 " x 35"
        Top Front/Back brace = 71 " x 2"
        Top Sides brace = 35 " x 2"
<I would make these braces wider... like twice, four inches>
      Additional Materials
        1. Tube of aquarium grade silicone
        2. Tape or clamps for holding the pieces in place
        3. Solvent for clean up.
        4. Rags/Paper towels for clean up.
        5. 1/4 inch wooden dowels.
      Getting Started
        Lay bottom, front, back and side pieces out on a large flat surface.
        Cut the 1/4 inch dowels slightly shorter than the length of the bottom. Place the dowels under the bottom piece of glass.
<What is this for? Just set the bottom glass on a level, planar surface>
It is important that the weight of the aquarium is supported by the front, back and sides.
There should never be any support under the bottom glass as this could fracture it.
<What? Is the tanks supposed to levitate?>
        Run a bead of silicone along all edges of the bottom glass. (these are the edges that will seal with the front, back, and side glass)
        Carefully place all pieces in place surrounding the bottom piece.
All contacting surfaces should have a bead of silicone.
        Use tape or clamps to hold the pieces in the correct position. When using silicone you will have plenty of time to make adjustments. Silicone can become a gooey sticky mess so you should keep the material and work area as clean as possible.
        Once all pieces are correctly positioned, let the aquarium set for 24 hours.
        After the silicone has cured, it is time to add the glass to the top. This piece of glass makes the sides stronger so the glass does not bow when the tank is filled.
        Let the tank cure in a warm room for 72 hours before you fill it with fresh water. If there are any leaks you can apply an additional bead of silicone to the inside seam. "
<...! I would run a bead in the inside joints during construction here... Make "grooves" with a popsicle stick, clothes pin... and trim, clean up later after curing>
        I am having a hard time wrapping my mind around exactly where the braces go.
<At, near the top, on the inside edges... the sides need to fit above or below the front and back braces...>
Secondly I have read avocations for both practices of bottom placement (inside the sides and front and back vs. sides, front and back placed on the bottom). Which would you recommend?
<Not on the bottom... need to be on the upper, inside edges... to prevent bowing>
Furthermore do you advocate the 1/4" offset of the bottom plate?
<No... glass should be on the bottom, but just on...>
        (Tank will have a 6" DSB thus the 30" height and plenty of surface area)
        Thank You,
        Ben
<Ben get someone to help you who has "been here, done this"... much easier to do with someone with experience. Bob Fenner>

All glass with no frame
I bought a used 65 gallon aquarium. It has no frame. All 5 pieces of glass are siliconed (only silicone?) together.
<Yes, just silicone.>
I see a bead of silicone on all the interior edges. The bottom sits about 1/2 inch above the edges of the sides, so the aquarium rests on the 1/2 inch glass edge of the four sides and the bottom
<As long as the sides and bottom are flush, I am ok with this.>
(and ~800 lb. of water and rock) is support by the silicone and whatever else is bonding the glass together. I filled it with water and have let it sit in the garage. It does not leak. BUT, does this construction make any sense?
<Yes, fairly typical.>
It has been a long time since my physics classes, but shouldn't the whole kitandkaboodle blow apart?
<No, the silicone is holding it together.>
Should I get/make a frame or should I give it to someone to put a lizard in and get another aquarium?
<If you wish to reinforce it, merely get three glass strips about 3-4 inches wide and as long as your tank is wide. Silicone these in place across the tank to act as braces, one in the middle and the other two on the sides.>
Thanks for your help! Mike
<You are welcome and enjoy your new tank! -Steven Pro>

Re: all glass with no frame
Robert, THANK YOU!
<Actually Steven then and now>
But, the sides are not flush with the bottom. The bottom sits 1/2 inch off the "floor" or stand and the entire weight is then carried by the edges of the tank.
<Oh, I don't like the sounds of that.>
The bottom of the tank does not touch the stand. And the tank is 24 inches deep (48 x 12 x 24). Does this change your opinion?
<How do you feel about Geckos? No, really, this seems like a really poor design. You could fill the bottom in with a sheet of plywood. Kind of like shimming the whole thing so that it rests on the sides and bottom. Maybe use 1/2" plywood cut to fit inside the sides and then a 1/2" sheet of foam insulation to absorb any irregularities. Or you could get anther tank.>
Thanks, Mike
<You are welcome. -Steven Pro>

Tempered glass for aquariums
Hi bob:
I have been playing with marine aquariums for about 30 years and still love em.
I have decided to build a 300 gallon tank 96Lx24wide 30 tall. Bottom, sides, and back are 3/4 plywood backed by 2x4 framing on 12 inch centers. the inside of the tank will be covered with a couple of layers of glass mat and polyester resin. The corners will receive an additional strip. A light blue tinting resin will added to the mix. The question I have is the age old glass thickness one. calculations say 3/4 is the correct size. Would 1/2 inch tempered glass work?
<Mmm, yes... if supported all the way around so itself wasn't the structure resisting bowing>
it still about $100.00 cheaper than 3/4 inch. Could I use 2- 1/2 inch pieces sandwiched together still cheaper than 3/4?
<No>
And yes the top of the tank will be connected every 2 feet.
Your thoughts on this will be appreciated
R. Luckert
<If it were me I'd spend the extra hundred dollars for 3/4". Bob Fenner>

Tank construction
>Hi there:
I am keen to construct my own tank in the range of 1000l to 2000l. I intend to initially use this tank for freshwater purposes and possibly convert it to a marine tank in a few years time. I anticipate it's dimensions as follows:
* length 2+m
* depth 0,8+m
* width 0,8+m
Please could you advise me on the most economical tank design in respect of the dimensions, glass thickness and bracing points. I also would need advice on the construction of a tank stand that would support such a mammoth. I would greatly appreciate it if you could send me some plans and include drawings if possible as i would like to make this a successful endeavour.
Are there any special construction methods available or will the use of
silicon do the trick?
Thanks for your help.  Don, South Africa
>>Hi Don, sorry this has taken so long, but here goes.
>>First, I need to do some conversions here, so..
>>2m = 79.75"
>>.8m = 31.5" on the nose
>>This will leave us with a total gallon capacity of 342.56 gallons U.S.  This is sizeable, but I have quickly found a link for you, with plans for a 500gal tank and stand here--> http://www.garf.org/140.gallon.html  
>>Now, these plans were designed specifically to rear corals and reef animals, but there is no reason in the world why you can't simplify and adapt.  The cost breakdown may or may not be of help, it would depend on your own material sources (and the exchange rate of $/Rand, yeah?).  
>>Because I don't really know what you have access to (where in S.A.?) I can only tell you that if it were me, I would go with a combination of glass and plywood (unless I had a good stock watering tub source).  Good luck!  Marina

Construction of glass tank
Hi, great work on this site! It's indeed a wonderful resource for all aquaria hobbyists. :)
I've some queries here regarding the construction of a glass tank. I'm planning to DIY a glass tank using 12mm glass with the dimensions 60 inches length, 36inches width and 22 inches height. Top bracing of 6 inches will be placed at the left and right sides, centre and along the top of the front pane and back panes. Would this tank be structurally sound and feasible? if not, which part of the dimensions would you suggest I adjust? Thanks.
Jay.
<12 mm (about 0.47 or half inch) is fine for the height... do want to make the usual statements re bracing (the top) to strengthen the tank against bowing, setting the tank on a level, planar (and strong) stand, floor... Bob Fenner>

Re: construction of glass tank
Hi Bob, thanks for the reply. Have another doubt here. I do have a friend who made a 4 ft tank b4. He said that the side panels, front and back should
be siliconed resting on top of the bottom panel. I myself have done some research regarding this and found some conflicting info. Some said the sides, front and back panels should be siliconed around the bottom panel while some others told me the same thing as my friend. Would like to know your opinion on this. Thanks.
<I have similarly heard, seen arguments for both types of construction. I and all manufacturers I've seen build the top pieces on top of the bottom. Bob Fenner>
Regards,
Jay.

Building my own glass aquarium...
(THE WIZARDS) da crew-
Your site has been a great help, but I was wondering what is the right type of silicone sealant or adhesive that I should use to build my tank?  The dimensions are going to be 60LX30WX30H and I was thinking about using glass.  It just seems that regular silicone caulk won't hold that much pressure.
<Well, it will. You can avoid problems by purchasing from a aquarium supply. I also suggest a good book or two on this subject....that's a lot of water!>
Is this some thing that I could find local at a home depot or
is it best to buy something from a specialty store.  Also I was
thinking 1/4" glass?
<GET A BOOK!!!! (or two) After you research this you will be SO happy you didn't use 1/4" glass and got the book. There are different grades of glass as well.>
If you could spare some time to help me it would be greatly appreciated, this would be my first tank. Thank you, thank you, Jim
<Take it slow, this isn't as simple as it appears. Gather the info you need before you lay your cash down.  Have fun!  Craig>

Thickness of the glass
Dear Bob,
Thanks for your quick reply again. Yes I am thinking of a frame of sorts running lengthwise would be a similar 14ft x 5" bracing. (21.5mm laminated also?)
<If can be cut in one piece, entire length, yes, but would cross-brace as well (over the top, front to back)>
So with this how thick should the front to back bracing need to be? Will 4" at one ft interval be enough?
<Would rather it was eight inches at two foot intervals myself>
When you are talking circumference that only includes the top right? Do I need any bracing for the top to bottom bracing at the 4 90 degree bends? I
have seen people use glass rods..?
<External... a good idea for a few reasons. Yes, I would have a/the "frame" run all the way around, but not underneath the structural tank. Hope this is clear. Bob Fenner>
Also do I have to repeat the same thing at the bottom of the tank to be on the safe side?
<No>
Okay just checking because I once had a tank 4' x3' 2ft wide. The tank maker
repeated the same kind of circumference bracing at the bottom too....
Thanks again for your quick reply, John

Re: Thickness of the glass
><External... a good idea for a few reasons. Yes, I would have a/the "frame" run all the way around, but not underneath the structural tank. Hope this is clear. Bob Fenner><
Dear Bob,
I sort of lost you on the last statement
It is quite difficult to find glass rods for the four corner. What I mean is you know the internal 4 corners?
<I wouldn't be so concerned re bracing the tank (made of glass versus acrylic) internally, or in this fashion... The external framing will lend some strength, but mainly protection to the glass edges...>
Where the four pieces of glass of the tank join together, do I need to reinforce with additional material like a small piece of glass plank?
<I would, on the top... run a width of glass... the four inches you stated... with the top cross-bracing on top and set inside the top front and back bracing strips... and the other cross bracing siliconed to the top of the front and back top bracing. If you have a drawing, please send this along here or fax it: 858-578-7372 in the USA.>
So with all the bracing running at the top I suppose I have to get a slightly taller glass as it will eat into my 30" viewing space right?
<No... the bracing is on top of the top edges of the tank... and on top of each other...>
Also with laminated glass the clarity is sort of diminished right? Like I would need more light to sort of see through the tank compared to a normal 12mm float glass?
<Much better clarity and strength with laminated glass>
I think when the tank is done I will snap some pictures for you to see, before I fill it up. Like that if you think I need extra bracing you can tell me..........safe than very sorry :)
<Yes. Bob Fenner>
Thanks again, John

Thickness of the glass
Dear Bob,
Here I go again.........!:)
I have been doing some last minute digging around and found out that so far most of the big tanks that I know of like a 14ft x 2.5ftx2.5ft and a 8'x4'x4'
are all using only 19mm tempered glass.
So am I going overboard by spec.ing 21.5mm laminated glass? the size I am happy with is 14'x2.5'x2.5'.
<Not overboard>
So how, please advice because if I can save a bundle I will like to .
<Better as the saying goes "to be safe than sorry"... theoretically (I always feel ill at ease starting off with this adverb) only height of a given system determines (or shall I preface this word with "should") what thickness of a given material viewing panel need be... the length and width of a system not figuring in as translatable torsional force... such is not the case in actual practice... longer, wider tanks do generally present "additional" stress on viewing panels... I'd go with the thicker material if it's not too dear>
Also the island where I live, there is so far only one group of people that I know that can get the tank together (experience I mean)
They want to charge me $1700 US just to glue the tank like labor charges. Is that too much?
<If you have the money, no>
I have to supply the rest like the reinforcement bars and silicon. Sigh.....
<I would, to make sure they're up to specification, yours>
The reinforcement bar I am told cannot be 12mm because that will not be thick or strong enough to do this job is it through?
<No... if I understand what you mean... I would at least double the thickness of the glass for the top braces, silicone together>
So for the top how wide a bar do I need, like usual I see for a 6ft is 2 additional front to back glass beams with a width of 2 inches
For my 14' do I have to have wider bars at every 1 ft interval? to prevent the front from bowing out? Can you recommend a design?
<Better to have fewer, but wider supports... is this entire system going to have a frame of sorts about the circumference/edges? If not, you need to have substantial bracing (like two feet wide for every two, three foot "gap" to prevent bowing>
Also do I have to repeat the same thing at the bottom of the tank to be on the safe side?
<No>
Sorry for the long one...........
Problem is here those who know how to do it will never tell me, sort of like a trade secret...........
<Not really secrets of this trade, but of structural engineering. I would contact my friends at RK2 for a further referral: http://www.rk2.com/ as well as the other "custom aquarium manufacturer" companies listed on WWM's links pages: http://www.wetwebmedia.com/links.htm and possibly who you can find there who is a real engineer. Bob Fenner>
Regards, John from Marineangels.com

DIY Glass Tanks
Bob I am new to your site and have looked through several of the FAQs but do not know where to post a question that you might be able to answer.  So I hope you do not mind the email.  If there is an appropriate place on your forums to post this please let me know.
<Hey Stuart, you've got Gage today.  Feel free to shoot us emails with questions, there is a ton of info archived in our FAQs and many knowledgeable folks on our forums as well http://wetwebfotos.com/talk/  >
I am interested in building a large tank, 94 by 36 by 48 inches high. Preferably out of glass.
<Never done it myself, I am considering plywood and glass myself, GARF does not recommend making the tank taller than 36inches.>
I am having trouble with the glass requirements.  Different tank builders have told me different specs, and I do not know which is needed.  One whom I am not sure I trust would uses standard ¾ inch glass.  2 others whose prices were in the stratosphere said they would use ¾ tempered glass..
<Error on the thicker heavier side.  From what I understand you cannot drill tempered glass, are you going to want drilled overflows?>
So my question is; making the tank out of glass, with additional ¾ by 2inch gluing doublers, is ¾ inch glass adequate, or is tempered glass or thicker float glass needed?  3 top braces are planned.   If so would an additional steel frame around the tank be required?
<Let me give you some links to some people who have more experience with this than myself.
http://www.garf.org/
http://www.ozreef.org/diy/index.html#TANK  >
Thank you for your time.  Any additional recommendations are welcome (I know don’t build it yourself :-) )  Thank you, Stuart
<No way, Go for it!  Just be sure to test outside, thoroughly.  A carpet cleaner with good extraction power is always handy.  Best Regards, Gage>

How to: build your own glass tanks
   My name is A.J. and I am looking for some helpful info on building my own glass tank.
<Okay>
  Particularly in the aspect of placing the sides, front and back pieces on top of the bottom piece or the sides, back and front
along the edges of the bottom.
<I used to build these (back in the late sixties to the early seventies, with the advent of Silicone and cheap triple strength (replaced glass from companies doing such repairs) quarter inch... building the tanks on their bottoms (mainly to assure flush joints there) and the sides inside (for ease in holding all together while assembling... with or w/o wood-clamps... we used to use tape or nothing (!) on smaller tanks while assembling)>
I read an article that told people to put a wooden dowel underneath the bottom piece of glass and assemble the all of the sides on the ends of the bottom piece to make sure that none of the weight would be on the bottom pane thus raising the bottom pane 1/8- 1/4 inch higher to prevent it from cracking. I am sure I have every thing else down pat except that one thing.  I would really appreciate your help in this matter
<Raising or more popularly "floating" the bottom has a few advantages, mainly per the issue of how level and planar the device is where the tank will eventually be placed, filled... if you can be assured the "stand" bottom is both planar and level (I would still place a thin piece of foam under it...) then I would do away with raising/floating the bottom. Bob Fenner>
A.J. Sacco