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FAQs about DIY Tanks, Sumps for Marine Systems 2

Related Articles: Making Your Own Tanks, Sumps, Designer Marine tanks, stands and covers, FAQs on Commercial, Custom and DIY Tank: Design, Shape, Materials: Acrylic, Glass, Other... Tools, Location, By Make/Brand/Manufacturer Name, & Aquarium RepairMarine System ComponentsCanopies, Covers & Lighting Fixtures,

Related FAQs: DIY Tanks, Sumps 1, DIY Tanks/Sumps 3DIY Tanks/Sumps 4, & FAQs on DIY Tank & Sump : Design, Shape/Size, Materials, Tools/Construction/Sealants, Plumbing... DIY Acrylic Tanks, DIY Glass Tanks, DIY Wood Tanks, DIY Other Material Tanks... & Tanks, Stands, Covers, Custom Aquariums, Stands, Covers...Acrylic Tank Repair


Replacing glass panes Crew: <Hi Rich, Don here today> I am trying to find an inexpensive way to have a sump. I had a brief thought (and brief may mean "ridiculous" to you), since I cannot drill glass: <I am always looking to save $$$ myself so I completely understand.> Let's say I buy an economical 10 or 15 gallon glass tank.  Then I remove one of the side panels from the tank.  Can I then cut a piece of Plexiglas, drill it for a bulkhead, and glue it in place of the removed side glass panel?  I am trying to avoid a complete DIY job, but is that what I basically have anyway? <I think you will find it difficult to seal the acrylic to the glass. In addition, I would worry about the plastic separating from the glass, Yikes!!! I just did this same thing and just went to the local glass shop and had them drill the replacement piece. It cost me $17 total for 16"x12" with two holes. There is no way I could have bought acrylic and drilled it for this price. After you get the replacement piece, save yourself a lot of future time and grief by removing ALL the silicon from the tank, cleaning the glass very thoroughly and then resealing the entire tank with the replacement piece in place. On an aside, have you thought of using a food grade plastic tub? Like Rubbermaid TM)? An option to consider. Don> Thanks, Rich

Glass thickness hello- thank you for taking the time to answer all of my silly questions. I've been reading all of the FAQ's and I'm still having treble determining the proper thickness my glass has to be for my tank am going to build which is 48"Lx24"Hx20"W.  I was thinking that 1/2" but I'm not sure if that's over doing it cause the price for these pieces of glass is over$ 500!! I could buy one for cheaper than that. would 3/8" be sufficient? Does the glass need to be tempered?  And once again thank you. Any advice would help. <Could be 3/8", doesn't have to be tempered... but should be braced "all the way around"... either from the top on all edges, or with a frame (likely wood, resin, fiberglass-strips or cloth), to reduce "bowing". Bob Fenner> THANK YOU JIM EUL

Building DIY Tanks Hello there: I am planning of building a plywood tank around 400 gallon, my dimension would be  84" long 30" large and 36 "tall , I would use 3/4 plywood with 1/2 glass or  1 "acrylic. I also would also paint the plywood with epoxy paint that i find at my local pool dealer (would that be ok) And also for extra protection I would had plexi-glass on all the epoxy paint and the plywood to protect against scratches and leaks . Would use GE silicone 100% pure  or GE silicone for aquarium uses, are they the same because the 100% pure is a little bit cheaper! How is  this sound for now???? And also because the acrylic seems to be a little cheaper ,is it better than the glass and would it stay with only silicone to attach it to the wood -epoxy paint?  And were can we usually find acrylic sheet?  Thank you very much for your help <Ahh....much to learn and much planning required here. 400 gallons is a heck of a lot of water, best to pick one system or another, either ply with attendant support, sealants, epoxies, glass or acrylic face, or all acrylic or glass.  Price is only one consideration of many necessary to be successful here.  Please do search at WetWebMedia.com for DIY information on building your own aquarium. I also highly recommend a good reference or two on this particular subject and the tech sheets for any materials you might choose so you know the proper thickness/tolerance for this much water in this particular dimension. My best advice, don't decide solely on price or cut corners in materials or information. Get all your info, decide on which is best based on need, cost, ease of use, etc. Then build according to plan. Best of luck, Craig>

My Acrylic Aquarium Greetings Wet Web Crew. Construction is finally complete on my 825 gallon aquarium 112Lx38Wx44H. As Bob predicted, 1" acrylic proved to be under designed with almost 3/4" deflection across front panel.  Wish I had found your site sooner. Structurally appears sound, visual distortion will be minimized by tank built into wall (front view only).   <Good> I am currently in the thick of filtration and lighting design plans and am hoping to get some feedback. I've spent the last several months pouring through FAQs and have learned a great deal.   <Again, good to see/hear> Aquarium will be a FOWLR set-up. DSB:  Have already ordered a pallet (2800 lbs) of Southdown sand from a Home Depot outside of Milwaukee WI.  Plan to use a 6" bed. <"Keep rinsing"!> Live Rock:  I'm planning to make a serious investment in Fiji live rock.  I am working with the assumption that I should fill approximately a quarter to a third of the volume of the tank with rock - somewhere around 1200 lbs (does this sound like a reasonable estimate?). <Mmm, I's start with about half this amount and see how you like the look... have it start curing (likely in place)> Including shipping to Minneapolis, Live Rock will be approximately $3.30/lb and base rock approximately $2.20/lb.  Any recommendations on how to split this?  All live rock?  50%LR / 50%BR?    <About half and half with the live on top> I don't plan to push the limits on bio-load for this set-up.  With this amount of LR, do I still need to incorporate additional external bio filtration? <Probably not> Frequent power-outages each spring would cause me to rule out a fluidized sand filter, would probably opt for w/d.  Should I also be considering some form of external mechanical filtration? <Yes> Protein Skimmer:  I have been looking at the AquaC EV-2000 (rated at 1,200 gph).  Will this be adequate for this set-up? <We'll see. Good choice to try>   Are there other skimmers for this size set-up that would be a better choice? <Maybe a EuroReef or two> Refugium:  Plan to use 2 150 gal Rubbermaid tubs with 6" DSB using a single 400W MH to serve both.  Will stock with a small amount of LR and use Macroalgae for nutrient export.   <I would opt for smaller compact fluorescent wattages or T-5's> Sump:  Still trying to decide whether I need a separate sump or whether I can use the second Rubbermaid tub for this purpose.   <You can/could> Lighting:  Ideally, I would like to provide enough light to maintain the coralline algae on the live rock.  Given the depth of my system, I assume I need MH lighting.  Would 4 or 5 250w MH pendants suffice, or do I need 400W? <What do you intend to keep and what do you want it to "do"? The smaller MH's will be fine... but you can have one or two 400 watters for placing over SPS, giant clams you want to boost physiologically> If lighting requirements becomes prohibitive, are there serious implications to the health of the system if the LR is starved for light (i.e. use standard fluorescents for viewing purposes only)? <This won't happen> Thanks much for your time and for sharing your expertise. <You're welcome. Bob Fenner> In your debt, Steve Walker

A Small Set-Back (catastrophic tank failure) Hello, Bob. Thought I'd share this evening's adventure with you and your readers.   My project of the past 6 months suffered a slight set-back this evening.  In the process of filling my 112Lx38Wx45H aquarium with water for it's second wet test, it suffered a catastrophic failure.  When the water was about 4" from the top, I heard the dreaded sound of a very deep thud (sounded like ice cracking on a Minnesota lake during the spring thaw).  Upon hearing the thud, I knew immediately the tank had failed and I quickly turned off the water.  Within a few seconds the entire front 1" sheet of acrylic gave way and my surprised wife (who was down the hall) later described the tidal wave of 800 gallons of water approaching her with a certain amount of disbelief.   <Oh no!> I've spent the last several hours wet-vac' ing the carpet in the basement - probably getting up around 100 gallons.  The rest will wait until tomorrow morning for professionals to come with industrial sized vacs and fans to finish the job.   <Money well spent> Three flooded bedrooms and a flooded family room all have very soggy carpeting. Storage rooms have lots of soggy boxes.  The aquarium room has holes in the dry-wall where the 6'x4' chunk of broken 1" acrylic was swept 9' across the room and into the opposite wall.  The 9' ceiling is wet where the water hit the wall and splashed upwards.  The dislodged acrylic broke a leg on a 6' ladder that was in its path as well as crushing a metal chair.  I am grateful that my kids were not in the room watching at the time - injuries would have been likely. <Have seen damage from such breaking tanks. Agreed> The top failed at almost exactly the mid-point of the middle cut-out (not at a corner) which leads me to believe the front face actually failed first.  I measured almost 3/4" of deflection on the front pane during the first wet test. <...> On the positive side, the aquarium failed during a test run with clean tap water.  It could have failed somewhere down the road with 800 gallons of salt water, 1,000 lbs of aragonite sand, and with significant live stock in tow.  I choose to be thankful for the circumstances of today. <You are wise here> I'm off to bed.  Tomorrow is going to be a busy day........ Regards, Steve Walker <Will you rebuild this tank with thicker material... or perhaps "cut down the height with the 1"? Bob Fenner>

Starting Over (800 gallon acrylic) Hello Bob and WWM crew, <Hello Steve> Following the failure of my 800 gallon aquarium two nights ago, clean- up is well underway.  Carpet has been pulled up, padding thrown out, baseboards removed, industrial sized fans everywhere, industrial sized de-humidifiers humming away.  It sounds a bit like the continuous drone of a jet engine in our house. <Thank goodness no one was injured> The cleaning service I hired suggested I was fortunate things are not worse and estimated that this will be a relatively quick clean-up that shouldn't take more than 7-10 days of aggressive blowing/dehumidifying to complete. I'd hate to be 'unfortunate' in this situation. <Have seen, been part of some of these cases> While much work remains to simply get back to the place where I started this project (not the least of which is carving up the remains of the old 1000+ lb aquarium and hauling it away), my mind is moving towards thoughts of starting over.   <Good> My aquarium manufacturer is re-grouping and is preparing their plan for a second attempt at this aquarium.  I intend to be a bit more involved in the selection of materials on this go-round.  Your thoughts would be greatly appreciated here (and I fully understand that your thoughts do not constitute an engineering recommendation and should not be relied upon as such). <Okay> It is my desire to maintain the original design specifications (112Lx38Wx45H). The price of acrylic seems to rise exponentially as thickness increases beyond 1". <Yes. It does> I believe I will find a way to fund the leap to 1.25", but this will likely be my limit and may need to adjust my design accordingly. <Okay. A comment re the cost of acrylic sheet... There is a "strata" of manufacturers, distributors, dealers... and fabricators can fit in most anywhere in this scheme... What I am trying to say is it pays to "shop around" for the materials here... There is a HUGE range of costs/pricing...> If I hold to the plan of 45" height, have you observed aquariums with these approximate dimensions constructed with 1.25" acrylic that seemed structurally and visually sound?   <On this run (length) of tank, the tallest I would go with one and a quarter material is forty inches... really. AND I would make the rest of the tank out of the same thickness... including the top and bottom of course> If you would be willing to offer an opinion, I will further ask what you would consider to be the maximum height for 1.25" acrylic and 1.0" acrylic, respectively (while maintaining a healthy safety margin and acceptable visual appeal)?   <There are a few stipulations (set on a flat, planar, level, strong stand... and that the cuts are clean, square... and the solventing done "appropriately"... and there is a factor for the length of the system... but all this taken into consideration, 36" height for 1" material all the way around... and forty inches for 1.25"... and for four feet of height... 1.5"...> No worries if you prefer not to speculate on these questions. <These are not speculations... our companies fabricated acrylic aquariums for several years (fourteen if memory serves)... and... yes, we tended to be overly conservative... as many of our sales and installs were in California (where the ground shakes considerably at times)... or sold to "unknowns" that might have not done quite as conscientious a job in some way/s that might compromise the structural integrity of our tanks...>   I understand they are better suited for the manufacturer - but nothing beats the opinion of an experienced and trusted aquarium fabricator. <Agreed> Thank you again for your valuable website and for your willingness to provide capable assistance. I remain gratefully yours, Steve <A pleasure to share, learn. Bob Fenner>

Re: Starting Over - Bob, <Howdy, Bob is in Brooklyn giving a pitch, today you get JasonC instead...> Thanks very much for your candid advice on acrylic thickness for my large aquarium re-design. <Indeed, what a story.>   Given the recent catastrophic failure of my 800 gallon aquarium, my tolerance for risk is gone. <I don't blame you.> A conservative design with an ample margin of safety is the only approach that will suffice - not only for my own well-being, but for my wife's as well - recognizing that I need to regain her trust and support before I can, in good conscience, move forward with another attempt. <I hear that.> Negotiations still remain with my aquarium fabricator regarding the losses I have incurred, but hope to quickly put that behind me and focus my energies on plans for a (safe) 40" high aquarium using 1.25" acrylic. <Do consider building in a margin of safety, either go with thicker material at that height, or lower the height - just to add to the fault tolerance.> Until that time, I hope to make good use of my second chance at designing my system.  More reading, dreaming, planning. <Sounds good.>   Best regards and deepest thanks, Steve <Cheers, J -- >

-Starting Over - Large Acrylic Aquarium Design Hello Bob, In our last correspondence, you recommended a thorough search of acrylic suppliers to find the most reasonable price for 1+ inch acrylic.  I was amazed at what I found.  1 and 1/4 inch stock varied in price from $570 to $960 for 4ft by 8ft stock.  Do you believe the quality of the materials offered varies enough to account for (or contribute to) these price differences?   <Not likely. More a matter of price differences due to lack of competition> I have modified my design/expectations to accept a shorter run length of 8 ft, instead of the 10 ft used in my original (failed) design.  I intend to use 1 and 1/4 inch material everywhere.  My design is intended to maximize volume with available 4'x8' sheet stock - 96"L x 48"W (possibly a bit narrower) x 40"H.  My question is as follows:  If 40" is the maximum safe height for this material, does the 40" limit represent the true height of the water column, or the combined height of base + walls + top? Put another way, if I use 1 and 1/4 inch base and top, are 40" Walls acceptable (resulting in total tank height of 42.5")?   <Yes, this last> Thanks again for your assistance. Best regards, <Bob Fenner> Steve

A little loose silicone sealant and very fine sand Howdy Crew, two quick questions today. 1. I used 100% silicone to add some baffles in my acrylic sump, but I am no master with the silicone tube, so a little smudged here and there.  I rubbed off as much of the extra as I could, but there might be a few very TINY little pieces of silicone that get in the water.  Can this hurt any of the animals, or the pumps for that matter? <No problems here> 2. Has anyone used substrate from pureAragonite.com?  I got the sugar fine, and it is REALLY fine, like flour in some cases.  Is this too fine? <Doubtful, though it may take a few days to clear, settle in your system. Bob Fenner> Thank you. Paul

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> Acrylic Tank Fabrication Not really a question. Today's list of questions included some about making you own tank. TAP Plastics, a somewhat local firm that deals primarily in acrylic, has a website that includes a downloadable set of documents concerning how to work with acrylic sheet goods. The link to their info page: http://www.tapplastics.com/plastics/plasticsinfo/acrylic.html Regards, Charlie H. <Thank you for this link. Will post. Bob Fenner>

Acrylic tank building Hello to the greatest crew on earth. <Howdy> Couple of quick ones I hope, I am considering building my own acrylic tank. Call it 48"L x 20"W x 24'H,( 100g ?). I was planning on 1/2" and wondered if a 3/4" x 1 1/2" solid oak frame around the top would be adequate to prevent bowing of the front/back. <Should be> Would you recommend any further front to back bracing? <Yes. At least a brace front to back on the top... or better, a solid piece with holes routered out for access... solvented along the entire top edges... like production acrylic tanks> Also I was planning on bending the front and sides from one piece, if I build a jig to secure the front could I bend the sides around a 3/4" dowel using a blow torch or would a heat gun be better? <... careful here. I strongly encourage you to just "butt" the corners together for this system. The heating gear for doing bends is more involved... easy to ruin many sheets in experimenting. Do you live near a manufacturer, fabricator that does heat-bending? Do call, visit them first if you're still interested in pursuing bent corners> I built my own 30g sump with 3/8 as well as my own overflow box with good success so I think I'm up for the challenge, any suggestions or pitfalls to look out for? <Mmm, many... make sure your cuts are square, clean... maybe use more viscous (thicker) solvent...> Also was planning two 1 1/2" overflows in back corners, would this be adequate for a 40 gallon sump.  I figured this would give me about 1400 gph? <Okay> As always your kind help is very much appreciated. <Have you considered making such tanks for others? I sense a pet-fish entrepreneur here. Bob Fenner>

Sump Baffles Hi All, <Hello> I have a sump question.  I read an old FAQ about an acrylic sump a guy was making and he wanted to attach a few acrylic baffles in it.  Bob mentioned that as long as they are not structural, you can avoid using the Weld-on product and just use silicone rubber, the type you find at the hardware store.  I got some stuff from Home Depot, 100% aquarium use silicone, I assume this is what he meant? <Yes> Also, since I will be adding two baffles, one for the divider of the first chamber to the second which will go from the bottom up about 9 inches or so with water overflowing over the top, and another smaller one a few inches high in just in front of the bulkhead to the return pump to prevent bubbles or whatever else, I assume these are not going to be structural in any way.  They should be able to hold back the weight of the water without any problems, using only the silicone.  Is this correct? <Correct. Give the Silicone a day to cure before filling the sump. Bob Fenner> Thank you Paul

Sealant for very large glass and stainless steel tank I have a project in progress of built an aquarium of  6,000 gallons of fresh water fish, will be with glass walls, I have everything figure out, the only thing that I would like to be help is to find a caulk sealer to help bonding or sealing concrete to glass , and glass to stainless steal. Or if you know a contractor will help a lot. I appreciated your help. <If this system is not too tall (up to six feet, 2 meters or so) and the frame itself is structural (that is, intended to bear all the force of the water, 100% silicone will do as a nesting, sealing material. Bob Fenner> Sergio Gonzalez

Glass vs. Acrylic Hi Bob et al, I am going to be buying an 800g aquarium in the near future and am pretty much sold on glass versus acrylic for the sole reason of scratch resistance.  I am concerned about the seals of the aquarium and how long they typically last.  I would really rather not have to drain this large reef aquarium in the future to reseal it.  Any idea how long silicone seals typically last in saltwater tanks?  Do you know of any acrylic tank manufacturers that sell tanks with more scratch resistance than the older acrylic tanks?  Thanks for your time! Dave <This is pretty straight forward..... The seals are a non-issue. They last as long as you will. The problem with your logic is, glass scratches too, and is permanent. Acrylic can be scratched easier, but can be polished (even under water) to resolve the problem. It is also lighter, stronger and better resistant to earthquake if that is a concern. It is easier to drill, install overflows, plumbing, etc. It is also more expensive. The scratch issue isn't as vital as you think. I have a few acrylic tanks and I don't have any visually distracting scratches or any I've had to polish. I *have* returned glass tanks with permanent scratches. Hope this helps!  Craig>

- Silicone Help - GREAT SITE!!! <And good day to you! JasonC here...> I was wondering if the is any specific technique to applying silicone to seal pieces together? <Don't skimp on the silicone, and the neatness of the whole thing is up to you.> I'm planning to put in Plexiglas baffles in a 10 gal. all-glass tank (being used as a sump) and also contemplating on building a corner overflow out of Plexiglas (not to mention drilling a hole in the bottom of my 55 gal. all-glass tank). <Well, you might want to investigate overflow designs first, and make sure you have all the tools you need - a router comes to mind. Next, spend some time at this link: http://ozreef.org/diy/#OVERFLOW - this will get you on your way for building an overflow. As for drilling the tank, I'd take that to a glass shop and have it done there.> I don't want to jump in and just do it, without professional advice, and end up having a leaky tank... or worse. Any advice on this matter would be greatly appreciated. <As long as asking for advice, see if you can cram a larger tank in there - a 10 gallon tank is ok, but likely it will only add about five gallons to your system volume... more water is always better.> Also, any recommendations on better/cheaper/sturdier material or material combinations (other than Plexiglas) would be nice. <Any sturdy acrylic will work - color is probably not important. Consider finding and visiting a large plastics shop where they often have a bin of cut, scrap pieces which can be had for pocket change. Will save you from having to buy a sheet of material.> Thanks a bunch in advance!!! Loyal WetWebMedia surfer Iona <Cheers, J -- >

Molded (aquarium) Frames Can you tell me where I can buy a molded top and bottom frame to construct an aquarium?  I have all the glass - just need the frames. Thanks <You can try contacting a manufacturer, like Perfecto, Oceanic... and see if they will sell these to you. 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.

How thick is thick enough? (custom tank construction) Hi, I have read hours of great ...GREAT info on this site!. I am building My own tank and I plan to start next week. It will be plywood and acrylic (Plexiglas) the dimensions I would like to build will be 96" long x 24" deep x 48" Tall, I have priced all of the items to include the very hefty 1" thick sheet of Plexiglas.... BUT?? will 1 inch of thickness be ok? also will 1" thick plywood be enough? The rest I can Handle through the outstanding idea's and instructions in your site, Thank you very much, Sincerely, Michael Waszak <Mmm, well... if this tank's viewing panel were braced all the way around it would do, but likely bow too much (to suit me)... I would increase the thickness of the plexi and paneling if it will fit your budget. Bob Fenner>

Re: How thick is thick enough? Thanks bob, I have decided to change the tank size to officially, 96x18x48.   with the 4x8 foot plexi @ 1" thick. do you believe that the glass and 1 inch plywood wood with these dimensions would cut down on the bowing? <These are the same dimensions as listed before (for the building materials)... the width (L X W X H) is not important here... the depth is. The "answer/response" is the same)> ( the master plan here is really a compromise, My wife Loves LONG! and I've always wanted a tall tank....) She plans on lots of smaller schooling fish. fish turning wouldn't be an issue (depth)......another question i guess would be should I drop down to 96X12x48? i really appreciate the time you give to help people like myself. I will send you a finished pic or 10 :-) oh yeah..It will be braced all the way around! <I think we/I am confused here... the middle dimension you list is the height? You can easily have this tank three feet (36" in height made of these materials with little detectable bowing, risk of structural failure. Bob Fenner> WHAT WE ALREADY DISCUSSED~ Hi, I have read hours of great ...GREAT info on this site!. I am building My own tank and I plan to start next week. It will be plywood and acrylic (Plexiglas) the dimensions I would like to build will be 96" long x 24" deep x 48" Tall, I have priced all of the items to include the very hefty 1" thick sheet of Plexiglas.... BUT?? will 1 inch of thickness be ok? also will 1" thick plywood be enough? The rest I can Handle through the outstanding idea's and instructions in your site, Thank you very much, Sincerely, Michael Waszak <Mmm, well... if this tank's viewing panel were braced all the way around it would do, but likely bow too much (to suit me)... I would increase the thickness of the plexi and paneling if it will fit your budget. Bob Fenner>

GE 100% Silicone I Hi There, <Howdy> I have seen several posts on the Internet saying this can be used as aquarium sealant. The company seems to be saying that it will only work with them under 5 gallons. Have you used this silicone on larger tanks? Thank you, Mike <This is exactly the same material as is used to make all sizes of tanks. I have used it on glass tanks of hundreds of gallons. Bob Fenner>

Silicone DIY - 2/12/03 Hi, I was just wondering if anyone could recommend an aquarium safe silicone, or how to tell on the container? <play it safe and order an aquarium brand silicone like Perfecto. For the few extra dollars, you'll have peace of mind knowing that it is non-toxic unlike most DIY store brands (anti-mildew...  anti-fish!)> Thanx as always, Jesse <best regards, Anthony>

- Drilling Tanks - Hello to all! <And hello to you, JasonC here...> I have talked to my local fish store about getting my 20h all-glass drilled to use as a refug.  They have asked me if the sides are tempered.  I tried looking on the side to see, but couldn't find the info.  I tried calling but business hrs are closed.  Would you guys happen to know if they use tempered glass for the side panes or not? <I don't think so. All Glass, one the larger manufacturer's in the US only puts tempered glass in a couple of their larger tanks... I think 55 and 75, but I'm 100% certain. I am pretty sure, though that you are safe drilling a 20.> Thanks, Jason-Surfs up! <Cheers, J -- >

Drilling a tank I have a 2 month old Reef Ready Oceanic 58 gal tank with a 1" bulkhead in the bottom.  The tank is currently set up with sand, live rock, fish, etc.  I would like to re-drill the tank for a 1.5" bulkhead to accommodate a larger pump (MagDrive 1800).  My question is, can I drill the tank if I drain only the overflow box or does the whole tank need to be drained? Thanks, Randy <The whole tank... needs to be taken down, drilled while empty. Bob Fenner>

My Acrylic Aquarium Dear Wet Web Crew, I am discouraged.  After reading today's FAQs, I am concerned that my new acrylic aquarium is under-engineered.  My 110"L x 45"H x "38"W aquarium is being constructed with 1" acrylic walls (7/8" actual thickness), 1/2" bottom, 3/4" top.  Bob's advice was to use the same material thickness for top/bottom as walls.  Further search for FAQs on acrylic aquarium construction lead me to conclude that 1" material may be inadequate for 45" height (salt aquarium).    <Mmm, I would have upsized the bottom... and looked into the cost of thicker material for the sides, front, back> Is this design unsafe? <Likely will be okay if placed on a good (strong, planar, level) stand> Am I going to be faced with excessive bowing?   <Subjectively... up to you to decide. If you're mainly going to be viewing head-on, likely not too bad> The top has not yet been glued on, so still have an option to reduce height (although I'm sure at great expense).  What is the maximum recommended height for 1" acrylic?    <About four feet... the bowing question is a matter of the "run" (length) of the system as well as height> I'm hoping for reassurance that the existing design will pass engineering muster.  At this point, safety is a greater concern than bowing - but I really need frank advice. <Should be fine. Bob Fenner> Thanks in advance.   Steve

Re: My Acrylic Aquarium (stand) Bob, Thanks much for your reply.  Making this kind of investment is unnerving.  Your response is reassuring, but I can see that I now have more work ahead of me to ensure the provision of flawless base support (stand).    <Yes, absolutely critical.> I plan to use a single layer of concrete foundation block for the stand with 1.5" of plywood between block and tank.  Concrete blocks will provide contiguous support under tank accept for areas where 4x1.5" bulkheads and associated plumbing run the length of the tank.    Bulkheads are planned to be cut near the edges of the tank (leaving about 2" of material between holes and edges).  Any concerns here about stand or about placement of bulkheads? <This whole apparatus is set on a concrete foundation? I would use a "water level" (the tank itself) to make certain of its planarity. Please see here: http://www.wetwebmedia.com/tksstds.htm>   Given my 1/2" thick bottom, am I introducing significant additional risk by cutting holes for bulkheads? <Yes... If this tank has not been assembled yet, I would have this bottom made of 1" material. Much to say here... IF a tank of your dimensions was built with the sides, front and back panels atop (as opposed to on the sides) of the bottom, this would not be such a concern... but cutting through the bottom for throughputs, and having to leave space around these to fit plumbing... makes me uneasy. Our companies used to fabricate acrylic aquariums as well as installing hundreds made by others... in Southern California... where the ground shakes occasionally. I like to shy on the conservative side here. I would either NOT drill the holes in the bottom (and instead make them near the top back edge) OR secure a thicker bottom. Bob Fenner> Thanks again! Steve

Re: My Acrylic Aquarium Bob, I am grateful for the advice.  The four walls of the tank are 'resting' on top of the bottom and are glued in this fashion.  Given this assembly technique, would bottom holes be acceptable? <Not for me>   Could I reinforce around the bulkhead underneath the tank by gluing an additional 6"x6"x1/2" plate (thus creating a 1" section in places where the bulkheads pass through the bottom)? <Unfortunately no. Have seen this tried time to time... too much likelihood of these added pieces joints failing. Bob Fenner> Thanks and regards, Steve

Re: My Acrylic Aquarium Bob, Thanks yet again for your response.  I see your point, and I have resigned myself to the fact that the meager thickness of the bottom leaves me with no alternative but to formulate a different approach to plumbing. <Yes... this tank will hold some 825 or so gallons... with water weight of 6,600 or so pounds...> If you have any patience remaining for me, I'll share a bit more detail about my original design, offer a possible contingency in light of the issue above, and then leave the door open for any suggestion(s) you might have. The aquarium is designed to fit an available space in my home.  I am dividing an unfinished storage room in the basement with this aquarium.  Walls will be constructed to frame the aquarium, and one half of the space will be finished as the viewing area for the aquarium. The other half of the room (behind the aquarium) will serve as the pump room, filtration area, work area, etc. <Good idea to have plenty of space.> The visible area from the viewing room is 9 feet (but an alcove area actually extends several feet beyond the viewing area).  Given that my local aquarium manufacturer was charging me for full 10 foot sheets of acrylic, I decided to build the aquarium 10 feet long with a 1" acrylic wall divider at the 9 ft mark and a second 1' wall at the 10 ft mark.    The intent here was to use the last foot as a sump that would enable me to draw water from the bottom of the tank, flow into the bottom of the sump, and then overflow into pipes 1-2" below the surface of the sump (i.e. tank water line).  This would allow me to effectively circulate water to the bottom of the tank, draw unfiltered water from the place where waste and detritus naturally accumulate, and achieve the benefits of a surface draw without any visible pipes or plumbing in the main tank.  If I spring a leak in my plumbing at any point down-stream, the tank will not drain below the level of the surface feed pipes.  The only risk to the system is obviously the plumbing connecting the main tank to the sump (a leak here will drain the tank). <Yes> Original Design: My original design was based on a UG filter to draw water down through a course gravel bed and out bulkheads distributed evenly across the bottom of the tank and deliver water to the aforementioned sump.  In previous dialogue, you encouraged me to avoid using UG filters and guided me towards a sand bottom.  Many hours spent mulling through your FAQs helped me clearly understand the logic of your recommendation and convinced me a redesign was in order. Redesign #1: Your recommendation to use a DSB now seems like the optimal choice.    The height of my tank (45") leaves plenty of room for the DSB.  I still wanted to incorporate the principle of drawing unfiltered water from the bottom of the tank, so I repositioned the location of the bulkheads from the center of the tank to back perimeter.  I designed a simple acrylic box structure (full length of tank, 5"W, 4"H) that will rest on the bottom of the tank, butted up against the back wall and resting over the (4) 1.5" bulkheads.  A small 1/8" opening runs along the full length of this chamber and protrudes above the DSB to draw water across the DSB, down into the chamber, out the bulkheads and up into the adjacent sump.  Bulkhead location in the bottom of the tank seemed optimal because it would ultimately suck out any detritus that settled into the chamber.  Keeping the chamber to the rear of the tank drove the requirement of locating the bulkheads as close to the edge of the tank as possible. Today's dialogue has again exposed flaws in my design. Drilling through a 1/2" bottom plate will push the limits of a marginal design. Anything short of full, stable support for a tank weighing 7,000 lbs, resting on a 1/2" sheet of acrylic is unwise at best - plumbing underneath is out. <Yes> Redesign #2 Where do I go from here?  I would still like to draw water from the bottom of the tank.  I would like to maintain a very clean tank interior (no visible bulkheads, stand pipes, etc).  I could keep this chamber concept alive by simply shifting the bulkheads to the rear wall (as you suggested) but my objectives above would require me to drill holes for the bulkheads leaving only 2" of material from the bottom edge of the sheet.  1" thick acrylic makes this less of a concern than the 1/2" sheet, but is it still to be avoided? <If practical. You could run plumbing for the main tank intake inside the system... with just one pipe (that you'd have to prime and cap... coming up, over the wall of the in-tank sump... But I encourage you to consider yet another possibility... of using space behind the tank for a much larger sump... having the water exit from thru-hulls in the sump area (if you'd like) with overflow and near-bottom draw of water to the sump from the tank... and batch processing, treating the water in the external sump... the internal one is going to be too much trouble (1' width is a pain to get in/out of as you'll see) and the circulation you'll want will be too much to draw in and move through it.> Is the concept of drawing water from the base of the tank to maximize the removal of waste and detritus valid? <Yes... but dependent on many other factors> Does my design concept of using a chamber buried within the DSB to unobtrusively draw water to the sump have a chance? <Not IME> I am open to rethinking the whole water flow design concept and would gladly leverage any learning's from your training and experience.  Of course, the tank itself (dimensions, material thickness, sump) offers little flexibility for change as it is essentially complete (small consolation - no holes drilled yet). <I see> I obviously should have done more homework before I started this project - I thought I knew more than I did.  Spending 10 years in the marine hobby from 1976-1986, with 5 years working for a LFS, helped me learn a lot, but that education seems to be about as useful today as my father's slide rule.  "My how things have changed". <Yes> I've learned a tremendous amount over the past month, thanks to your website and all of the resources present, not the least of which has been your personal council. I've read Paletta's book and have yours on order. I'm playing 'catch-up', and intend to learn a lot more before this aquarium is officially launched. <You'll do fine> Again, thanks for your ear and for your guidance to date. Regards, Steve <I wish you lived close/r to San Diego... we have a hobbyist club here with folks that have large systems as yours... who have gone through similar approaches, trials... You could simply visit with them, see what they have done. I would abandon the current design, and add a large external sump (like 200 gallons... like a polyethylene tote...) and likely drill the tank, attach street elbows to the bulkheads (to adjust overflow of the main tank height... and do some dreaming, scheming re pump choices... Bob Fenner>

Re: My Acrylic Aquarium Bob, Again, thanks for the advice.  Living in San Diego certainly has its appeal - its a bit warmer than Minneapolis this time of year..... <Brrrrr~> An additional external sump makes sense (fed from the small sump attached to the main tank).  I also like the idea of feeding water from the main tank directly to the small sump through the dividing wall (surface overflow and near bottom draws). At this point, you've got me convinced to get rid of external plumbing all together, if possible. <Ah, good> Is there any benefit to drawing water from near bottom on both ends of the tank (accomplished by running a piece or two of 1.5" PVC under the DSB from the far end of the tank into the small sump), or is drawing from only one end of the tank adequate (nine feet seems like a long ways to pull from only one end). <Better to not complicate things here... with sufficient water movement no worries re detritus accumulation. Do take a read through WWM's marine plumbing areas... starting here: http://www.wetwebmedia.com/pbfaqsmar.htm and on for much more input on possibilities. Bob Fenner> Thanks and regards, Steve

Re: My Acrylic Aquarium Bob, Thank you for your time and helpful advice.  This is a great website and a tremendous resource for the hobby.    <Glad we have found each other> I'm off to read up on plumbing, sump design,..... <Ah, good. Bob Fenner> Steve

Re: diy acrylic aquarium Thanks Bob for the quick response re. my 72"x20"x24" acrylic thickness but it brought up more questions. First, does it matter if the sides "frame" the bottom panel or can they sit on top of it? <Better to build the sides, front and back on the bottom> If they can sit on top, why does the thickness of the bottom piece matter if it will be totally supported as acrylic tanks should be) by the stand? <Mmm, helps to resist shearing force... by uneven support underneath (the stand, what it in turn sits on)... the most force is actually on the bottom> Does thinner material (3/8" vs. 1/2") "stretch"? <Yes, to a small extent more> I've already got the material and am trying to avoid spending any more $$ unless I HAVE to? My wife is rooting for no more material, but I think she will be much more upset if 150g hits the floor! Thanks again, Scott <Agreed... if you haven't cut the sheet and the paper is still on it, ask the supplier to allow you to trade it in for 1/2"... This is what I would do. Bob Fenner>

Re: diy acrylic aquarium One last question...for now. Do you know if it would be possible to purchase 1/4" acrylic and solvent bond it to the 3/8" to "create" a 5/8" thick piece for the bottom (as an alternative if the acrylic guy won't exchange 3/8" for 1/2") Or am I grasping at straws that don't exist! <The latter. Bob Fenner>

Re: diy acrylic aquarium I am making my own 72"x20"x24"h acrylic tank. I am using 3/8" for the bottom and 1/2" for the sides. <I would make the bottom (and top, see below) at least 1/2"> I am planning on two 1 1/2" overflows that will be located in a 5"x20" overflow box built into one end as this tank is sitting on a partition wall and will be viewed from the other three sides. First, will these overflows be sufficient if/when I gradually progress to hard corals? <should be, yes> Second, I was planning on using 3/8"x3" strips of acrylic to make a rim around the top of the tank with three 3/8"x5" strips used as bulkhead braces (front to back) spaced evenly. <I would make the top one piece, route out the openings for access> Will these "strips" be sufficient to reduce bowing or should I get a solid piece of 3/8" and make cutouts as is commonly done? And is 3/8" thick enough for the top? <Make the top, bottom, at least as thick as the sides, front/back. Bob Fenner>

- Using Hot Glue - To Whom Is Every Covering: <It's JasonC today, greetings.> I am setting up a new sump and was informed that the skimmer should obtain as much raw water from tank as possible. <As much as is practical, sure.> I am in the means of sectioning off a 29 ga. for my sump for the 90 ga. tank above. My question is: Can I use hot glue to secure my  1/4 inch acrylic section to the tank? <You could.> Will it leach out anything harmful? <No.> And do you think it will hold? <Not really, no.> I do not know the amount of pressure 1/3 of the water will exert on the acrylic section. It is the easiest, I also have epoxy polyurethane, as well as silicone available. <Silicone is probably your best bet.> Thanks for your response. Regards, Mendy1220 <Cheers, J -- >

Formula for glass or acrylic thickness for homemade tank? WWM crew. Any formulas for glass, acrylic thickness for diy tank. Built myself a 5x2x4 marine plywood tank, need only to add glass or acrylic. Was planning on using 1 1/4 inch acrylic. Tank is to be live rock holding tank, refugium, plumbed in my 450 gal reef tank. Used double thickness of 3/4 inch marine plywood in its construction. Built better than my house! Wanted to use glass for ease of cleaning but leaning towards acrylic for strength reasons. Sheet needs to be 46x58 inches. Any ideas, formulas much appreciated. <<Hi Paul, I don't personally know of any stock formulas, but a structural engineer would. Also you can read here http://www.wetwebmedia.com/diytksfaqs.htm and beyond for more ideas. There are many aquaria diy sites that you can check as well, www.ozreef.org is one you can investigate>> Thanks as always.   Paul << Your welcome, Don>>

- Tempered Glass - Hi, Guys <Hi, JasonC here...> One quick question, I am getting a glass sump made at a local glass shop. There suggesting that the end piece were the wholes for the bulk heads will be drilled, for the return pumps, should be tempered. Of course they want more money for this. what do you think???? <Hmm... well, the people at the glass shop really should know best - that is the business they are in. The company All-Glass makes some of their tanks with tempered glass, but recommends against drilling them. This may have something to do with the fact that the tank is already assembled. You might want to ask your glass shop why this is, but again... they are the professionals and they 'should' know best.> Charlie Newbie <Cheers, J -- >

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>

The Shadow! A few questions.. <Hope I can provide a few answers! Scott F. here tonight!> I have a 55 gallon all glass tank with an all glass internal overflow in left hand side. I'm running 96 watt pc's and a 250watt metal halide bulb that's in the center of the tank.   <Sounds like a nice setup!> First question. The tank has a hideous black separator at the top in middle of tank, I guess to support those cheapie light hoods.  It's quite flimsy and doesn't seem to be providing much support.  Anyway, my metal halide bulb is about 4-5" above it, and the >black partition casts one hell of an ugly straight line down the center of my tank (a shadow). <Yuck...> Can I remove this black piece of plastic?  I mean, is there a "rule" saying that the plastic is for structural integrity of the tank and shouldn't be removed?  I just thought it was to support an acrylic or glass hood, in the middle. <Well, I wouldn't remove it...No way! uh-uh...Anything that holds together a large glass container of water stays intact, as far as I'm concerned!> Next question: After a power failure recovery, my return line shoots out quite a bit of air mixed within the water.  This causes a burst/splash at the surface of the water and it splashes up a few inches.  My metal halide bulb is perilously close to this splash when the power comes back on.  I'm afraid the bulb will burst when the cool water hits it. <Valid concern> I need to figure out a way to prevent the return from sucking in so much air when the prime breaks to prevent reverse siphoning of water into my sump.  Is there a modification I can make down in the sump above my main pump (where the water heads up to the tank), that allows air to escape upwards while allowing water to gravity feed downwards?  Some sort of pvc elbow perhaps with a vertical tube like 8" long to allow air to go into it as water bypasses it on the siphon way down into the sump? <That sounds like an interesting idea..> I'm just guessing that may work but wanted clearer instructions on how to correct this problem. <I'd give your idea a shot...it might just work!> Thank you all , once again, for your time and patience in answering all my questions. Regards, Steve <Good luck to you! Regards, Scott F.>

Re: Support bar on tank Scott, Thank you for your comments. Do you think you could forward my email to a few other members so I can accumulate their thoughts as well? I really would like to remove the thin black plastic separator from my tank, as well as find a cure for my return line air/splash problem. <You mean the center brace on your tank? Dude....I wouldn't do it unless you are absolutely, positively sure that it's not part of the tank frame. Personally, I think it IS part of the tank frame therefore I would never attempt to remove it. If you can live with the consequences if the removal doesn't happen successfully give it a shot. But let me reiterate...I would leave it alone> I spend about 2 hrs a night on the wetwebmedia.com site filtering thru the FAQ sections, but have yet found a solution to the aforementioned problems as of yet. <As far as your splash problem...I have the same thing happen on my tank when the power goes out. I have accepted the problem because it doesn't happen very often. If you want to try something use a check valve above the return pump (I don't like them but you may). If it were me I would buy some kind of cover for the halide (like a UV guard) and let it go at that. It's cheap and easy> Warm regards, Steve <Hope I've helped! David Dowless>

Re: Support bar on tank Dear Dave, The top piece of plastic....well, I don't know what you mean by it being "part of the tank frame". It's connected to the black plastic that wraps around the top of the tank...typical of all tanks. <Can you just lift it off or will you have to forcefully remove it? Is it for aesthetic appeal or does it have a function? I haven't seen it so I don't know> My question is "If i were to have a tank built by a glass maker, he wouldn't put any plastic brace in the middle.  The top would just be wide open." <Okay> So i was just wondering if anyone u know has ever removed it?   <I haven't and wouldn't...I don't know of anyone that has...> You mean to tell me that EVERYONE has this hideous black line going down the center of their reef tanks due to the shadow it casts? <Like I said...If you're a gambler, pull it out...gently. If you're right about this, you will be happy. If I'm right about this, sooner or later you'll be replacing your carpet and rebuilding a tank. It's your choice...really. But from this distance, without seeing it for myself, I refuse to encourage this...doesn't mean you CAN'T do it. Let me know how it turns out> Thanks, Steve <You're welcome! David Dowless> Re: Support bar on tank Dave, It's me again. I didn't get this email until I already sent my last one.   My tank is a standard ALL GLASS tank that you see at the LFS.  It's got the standard black edging all the way around, and the top is plastic with a black plastic separator in middle of top so a light will have a place to rest an edge on, or two separate glass tops can be placed on without falling into the water. When I wiggle it, it has some flex to it and doesn't seem rigid enuf to provide structural integrity .  I mean, I was going to have a tank built at my local glass shop and there were no plans for any type of center piece at the top.  He was just using 7/16" glass all the way around like a rectangle, that's it, with silicone sealant on all joints.  Maybe you could ask around for me if anyone else has removed it. Regarding the backsplash on my return line after power comes back on....where do they sell U.V. guards?  Can i just use a piece of clear glass over that spot where the water splashes?   <I would contact the manufacturer of the lighting system. I'm sure they will sell some kind of cover for your lights. Clear glass would shield the light but it would also distort. Contact the manufacturer> They say you should never use any type of cover below your lights, as this decreases light intensity into the tank, so i am concerned.   <That's why I said not to use glass. You simply need to find the right type of cover> have a 55 gallon aquarium that is about 20" deep or so and has two 96watt power compact fluorescents with reflector and a 250watt Iwasaki MH bulb in center. Thanks again. Steve <I hope I've helped. David Dowless>

Re: Support bar on tank Dave, <Yeeeeeeeeesssss....> This was my response from the tank's manufacturer when asked if it'd be safe to remove the center brace from the tank. <Great!> <All right my friend...score one for Dave! I know the shadow is an aggravation. If I were you I would look for some way to arrange my lighting so that it doesn't shine directly over this bar. Another idea is: How about a small, let's say an insignificant light, that will be just enough light to break up the shadow effect. You could mount it to your canopy so that it shines directly through the shadow. Correct placement is the key. I would definitely experiment with the light before mounting and let me know how this turns out. Now aren't you glad you didn't move that support? I have owned an All Glass tank and they really are good quality and apparently provide good customer service IMO. David Dowless>   Hello Steve, Though your aquarium would not collapse after removing the center brace it would suffer a loss of structural integrity which could cause leaking or cracking of the glass down the road, not even to mention how the glass would bow. I am not sure who the manufacturer of your friends aquarium is and if it is one of ours it's very old. I had been building aquariums here for 20yrs, producing 55 gallon aquariums with center braces for around 17 or 18yrs. With the injection molded frames having center supports we could reduce the glass thickness of our aquariums. Which resulted in a lighter aquarium that didn't cost as much. Had we not gone that route the aquarium hobby would not have been able to have grown like it has, the aquariums just would have cost too much. I'm sorry..... I'm not sure how to get around the shadow issue. What I would recommend is just what you are doing, which is seeking answers. If you wouldn't mind letting me know I would be very interested in the solution you find. I'm just not hearing the complaints of the center brace casting a shadow due to the light unit, so don't know how to advise. Best Regards, Dawn M Zimdars All Glass Aquarium Customer Service Supervisor (800) 255-4527 Phone (414) 421-9670 Phone (414) 421-4195 FAX

Paint Me Cautious! Hi there <Hello! Scott F. here today!> I have 2 quick questions for you: 1) Is enamel paint safe for inside the aquarium? <There may be some "marine grade" enamel varnishes available, but I would definitely refrain from the use of enamel paint in aquariums. Better to err on the side of caution, IMO!> 2) I have some red shale rock I was going to use to decorate the inside of my aquarium with.  If I were to paint it different colors with enamel paint would it be safe for the fish. <I'd have to say no. If you do want colored rocks, there are a wide variety of "made for aquarium" aquascaping materials (artificial and natural) that may fit the bill.> Thank you for your time <And thank you for writing!> Silicon and moving 125G tank Hi Gang, I hope you all had a great holiday season and Happy New Year!  If this is Anthony, it's been awhile and my tanks are great no problems!  I will be moving both my 125G and My 90 gallon into the basement with my new home office.  I will have more space, and both tanks in the same area.  Here is the question.  With my 125 move I want to adjust the sump slightly.  This will involve some new partitions that will be siliconed in place.  If I remove the sump first, put in the new partitions, than say 7 hrs later when the move is complete, add back in the livestock, will this be enough time for the silicon to not be an irritant to my corals and fish?  I am not worried about strength, it's the curing time and irritation I am worried about.  Thanks  Larry <I would not submerge the silicon for a good 24 hour period, to allow it to cure completely. Bob Fenner>

Aquarium paint hi there, i just recently stumbled upon your web site and i have to say its awesome.  i have got a lot of good ideas and it has answered many of my questions.  i was wondering what kind of silicon was safe but then i found on your site that any 100% silicon is safe for use as long as no additives are in it.  anti mildew etc.. <Yes> the one question that i could find no solid answer to is which paint is suitable for use underwater and is safe for the fish.  on the many sites i have looked at including yours i have seen everything from tub and tile epoxies, paint to latex paints, resin, and rubber paints .  i have searched your site to the best of my abilities and i can come up with no straight answers.  perhaps you could answer a couple simple questions for me. which paint and epoxies are fish safe? if tub and tile is one of them is this a brand name or any brand made for tub and tile? <Any>   i looked at the local hardware store today and could not find any "baby safe" as your site had suggested. <Ahh, likely a matter of liability. All of the above materials, once cured are safe for aquarium use. A few comments re the choices. The tub and tile epoxies have the longest service life. Resins tend to "white out" become opaque underwater with time (weeks to months). Latex and rubber paints are most likely to "let go" peel off in time, and the last are tough to properly cure.> thank you for your help i am becoming frustrated at all the different info i find.  today i asked at the pet store which paint is suitable and he replied "any as long as its dry".  i found this extremely hard to believe. <Me too> Happy New Years to All Ron Villeneuve Canada <And to you and yours. Bob Fenner>

DIY Aquarium Is fiberglass resin toxic to fish? There are many kinds of resin. Polyester marine resin would be suitable for my project, epoxies might work too. If so, are there ways to pre-cure the product so there more compatible before introducing fish? Just looking for the right building materials for the aquarium and don't want any victims on my hands. What do you recommend? <Please take a look here for the article on working with fiberglass, http://www.wetwebmedia.com/PondSubWebIndex/fibrglsconstr.htm. This one is about pond construction, but it should cover many of the same basics. Also, follow on through the linked FAQ file and the bibliography for additional information.>  Thank you for your time. Aloha, Sandie <Have a lovely day! -Steven Pro>

Center brace for a 100 gallon tank I recently purchased a used 100 gallon tank.  i need to put the center brace back in place and was wondering if regular 100% silicone caulk is strong enough to hold it or should some other type of adhesive used. <The silicone is the route to go... used in skyscrapers...> the tank is made with 1/2 inch glass with 4 supports on the bottom of the tank. on trips to my LFS i noticed tanks have "shims" attached to the front and back glass with the brace resting on them. <Yes, used for installing the center piece which in turn serves to brace, keep the sides from bowing> thank you for the help!!!!! <You're welcome. Bob Fenner> JimB

Building big tanks Hi to all, <cheers> I have a 55 gal corner bow front salt water tank.  It was way overcrowded when I found your web site. It now houses a russelli lionfish.  I got rid of the panther grouper, blue line grouper, red emperor snapper, snowflake moray, and crown squirrelfish.   <holy cow!... you weren't kidding about overcrowded! The Red Emperor alone would outgrow this tank... fast growing... and tasty to eat> The Lion fish seems to be much happier.  His side fins are always extended now and he has stopped racing back and forth across the side of the tank.  (both of which I thought were normal)  Thank you for all your help and for a Great website. <excellent my friend> Now to my question.  I am going to be building a tank in the future and the available space I have will be such that you will be able to look through the tank from one room to another.   <have you built smaller aquaria before? It is simple but requires great finesse. Very little room for error in fabrication> The size that I can go up to is 8' long 4' wide and however high is best.   <wow... my strong advice is to not do it without the assistance of someone that has experience here. Especially if you have housemates (wife/children, etc). A tank this big improperly built is a several thousand pound hand grenade. You have several big obstacles here. Primary concerns are the cost of materials (cost prohibitive for your single purpose endeavor compared to skilled merchants buying materials in bulk and knowing what to do with them)... and #2) any tank (glass or acrylic) that exceed 30" wide or high takes the project to another level entirely and requires engineering/data. Brother... that's why all commercial glass aquariums and most every off the shelf acrylic ones are less than 30" wide or tall. Length is not much of a problem though with bracing. The problem with tanks over 30" is the inherent limitations of the material with regard for deflection ("bowing"). Plate glass is limited (safely) by a deflection not more than half of its width... so, a 1/2 pane of glass should bow no more than 1/4". Your proposal at 4 feet wide and who knows how tall will require laminated glass (moved with winches for its extreme weight) or VERY expensive acrylic. This is out of our league here bud> The two things I am looking for is a book that describes in detail how to go about such a project (know of any?) <ahhh...no. Liability issues here. Some human safety factors as well. Please check your insurance limitations as well> and also whether or not I can keep all the necessary apparatus in the basement.   <that you can do easily> Is that even possible and are there pumps capable of overcoming that much head (approx 12') <oh, yes! Many hobbyist pumps will easily do that. Many can go 30 feet! Do research an Iwaki 100RLT. A durable and affordable workhorse. Long life and efficiency too> Again, Great site and I really enjoy reading the new faq's everyday. Bryan Flanigan <best regards, Anthony>

Re: building tanks Hi again, Just a follow up to my last about building tanks.  I was as usual unclear about what I was looking for.  I am not actually going to build the tank unless I have to, and all the dimensions are able to be changed.   <excellent... do seek a commercial unit for safety, expense and peace of mind (both of our <G>)> The addition to our house that will house this new tank is still in the design stages. 8' X4' X ? was just a guestimate. So, a Tank 8' x 30" x 30" is just fine.   <Excellent... you will have little trouble then> What I am looking for in a book is direction on how to set it up, what kind of flow rates I need, how large a sump, how many heaters, etc, etc.   <seek "Aquatic Systems Engineering" by P. Escobal. Very intelligent but dry/scientific authorship> I do not wish to repeat the experience I had with our 55 gal.  I have loads of extra stuff that I thought I would need and am still missing stuff I now know I need (skimmer).   <yowsa... maybe skip the above book unless you are a science man yourself (tech minded). Do consider John Tullock's work in general or my Book of Coral Propagation for reefing (the first 200+ pages all husbandry/hardware)> So since this is going to be a fairly large tank and expensive as well, I need to learn as much as possible before we begin shelling out the dough.   <very wise and agreed> once again a great site and thank you Bryan Flanigan <best regards, Anthony>

Building Acrylic Tank Dearest WWM Crew, <Hi Shawn> The best piece of advice I got when I asked about beginning in the marine aquarium hobby was READ READ READ. Thanks to your site I haven't had to go far to log over 100 hours of reading just on your site in the last two weeks. I've kept fresh water tanks since I was a young child and have been very successful at it, breeding everything from livebearers to some quite difficult tetras. I've decided to start with a small semi-reef environment to experience the basics with plans to build a much larger than normal system in the next year. My problem arises with probably what I figured to be the most basic of formulas and was hoping that since I haven't found it anywhere else on the net or your site that maybe in your all-but-omnipotent knowledge someone there might be able to help me out. Is there a specific mathematical formula for finding the pounds per square inch exerted by salt water?  I hope that made sense, lol, I know that water as it pertains to aquariums exerts more force on the top of the aquarium as opposed to the bottom, my problem is finding a formula for figuring out what material tensile strength I need to build a specific sized aquarium...any help you could offer would be greatly appreciated. Sincerely Yours, Shawn King, AKA reefrookie <Yes, there is a formula for figuring out the thickness the material should be based on the height, length, etc. These formulas are specific to the various types of materials, glass, acrylic, etc, and subgroups of these based on formula or proprietary differences. Many of the acrylic manufacturers offer product fact sheets containing this information as it is specific to their material. I would start with the manufacturer of the material you want to use. Craig>

Acrylic Hi guys, quick question. I am in the process of making an acrylic sump. Had everything cut.. sides, dividers and have all the glues ready, but I screwed up a couple pieces tonight trying to take just a little bit off the sides (and now I need some new pieces),!@##*...bad night. Here lies the problem. There is no place in my town to get the thickness I was working with. So I had to order everything to begin with. My sump dimensions are... sides 30"x16" and the ends are 16"x16". Was using .177" or 3/16" acrylic and even had some 1/4 from another time. The only place that sells acrylic has it in .100" or 1/10" do you think this is to thin for my sump? <Too thin for me... unfortunately... not enough bonding surface... and will bow too much... I would hold off till you have the 3/16" material> Will still use 3/16 and 1/4 baffles/dividers, probably 3 of them in the sump. Let me know what you think. Thanks again, Bryan <Patience my friend. Bob Fenner.>

Building acrylic tank I just found your site and have been looking around it. Very nice, I plan on looking more. <Okay> I was trying to find a formula on how thick to make an acrylic tank. I noticed in the /dessysfaq2.htm page you talk about 1/2" vs. 3/4" on a 24" tall tank. I've got an idea for a tall tank, but not sure how thick to make. I had a few companies quote the tank but some say 1/4" some say 1/2". I understand about the bowing being reduced with thicker material but eventually there must be a minimum thickness decided by a formula. <More like "general guidelines... there is some "fiddling" with these rules of thumb depending on a few factors... length, earthquake proofedness, surface/top bracing... quality of material used (this does vary)... I would likely go with 3/8" and maybe opt for a bit thicker material for the bottom... 1/4" will bow too much... and thicker all the way around is too expensive/rich for my blood> Can you tell me where I can find this formula? Thanks, Steve Larson <Due to the litigiousness of this society, I doubt if anyone will/can refer you to such... I'd check out the systems made for resale, go with at least what they are made of. 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>

SMALL DIY Tank Dear Bob, Most of the help I can find on the web is for REALLY large DIY tanks. I am interested in constructing an equally small one. I am trying to go the least technical route b/c I have limited experience with tools but always want to try. I would like an aquarium about 10"d x 18 or 20"l x 10.5"h, and I would like it to be lighter than glass and moveable (not while full of water). This is kind of like a short 10 gallon-- Not an available aquarium size. <Okay> I am wondering if I could make such a tank out of 1/4" Plexiglas, with a wood frame. <Yes, could be done> From what I've read, I understand that the plexi-to-plexi bonding would require something like Weld-On. <Yes, or similar solvent> What about bonding the plexi to the wood frame? <Only for looks in this size, shape system. You could use a smear of silicone to hold the wood together and to the plexi> Or is a frame not necessary for strength of the Plexiglas? <Correct> If my project is even possible, could you please help with a general description of the steps that should be taken in constructing a small tank with plexi and wood? <Measure, cut the pieces, tape or clamp the pieces in relative place, squirt/place the solvent... let cure for a day...> I can handle plexi, glues, wood, staining, nails and screws, but I'm afraid I have trouble with anything much more technical than that (marine plywood, epoxy, fiberglass tape...). <Not necessary to be/get too involved> Thanks so much for your help. Your website and FAQs are really helpful. I hope I can do you proud :) <You have my friend. By being, expressing yourself. Bob Fenner> Jill Petersen Atlanta, GA

90 gal aquarium Hi. Like to say that there is some great info on the site. <thanks kindly> Im in the process of scraping some money together to build a 90 gal saltwater aquarium. I plan to make it out of 1/2" acrylic. Dimensions of 48"x18"x24". Calculator says it should be about 90 gals. Im also gonna glue in a top brace for added support. <will certainly be necessary. And are you working from specs with deflection tolerances of the material that you've bought or are you just building a hand grenade? <G>> My question is, can I build a 180 gal with the same materials and same dimensions except the width being 36"?  <While I am not an expert on acrylic, I can tell you that glass aquaria wider or taller than 30" cannot safely be built without a four sided capture (welded angle iron/steel, etc). And since 1/2 glass suffers less deflection than acrylic, a 180 will 1/2 acrylic is unlikely to be sound without very intrusive bracing if at all> I'd like to give my silver Pacu a little more room to grow in.... What do you think? <I agree... the Pacu needs much more room. Anthony>

Kent products Hi again <cheers, my friend> I bought your book from Amazon, but it is going to take like 15 days before I receive it in Colombia. I am really looking forward to read it.  <I hope that you enjoy it and find merit there too. Read it in good health :)> sorry I didn't bought it from you but I find after setting my order that it was available trough your web page. <no worries at all> I would like your advise in Kent skimmer and wet/dry rocking filter. <I'm sure that you can find a much better skimmer. Are any of the following brands available to you: Aqua C, Euro-reef, Tunze (first choices), Turboflotor, Klaes are also good. And regarding the Wet/Dry... I would suggest that consider making one yourself. They are simple and you can make one that will serve your specific needs better and save money by building it. Many DIY plans on the internet including here: http://www.ozreef.org/diy/index.html there are about a half dozen links to plans at the very bottom of this long page. Best regards, Anthony> Best Regards
Andres Saravia

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