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FAQs about DIY Tanks, Sumps for Marine Systems 4

Related Articles: Making Your Own Tanks, Sumps, Designer Marine tanks, stands and covers, Aquarium RepairMarine System ComponentsCanopies, Covers & Lighting Fixtures,

Related FAQs: DIY Tanks, Sumps 1, DIY Tanks/Sumps 2, DIY Tanks/Sumps 3, & 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... DIY Acrylic Tanks, DIY Glass Tanks, DIY Wood Tanks, DIY Other Material Tanks... & Tanks, Stands, Covers, Custom Aquariums, Stands, Covers..., FAQs on Commercial, Custom and DIY Tank: Design, Shape, Materials: Acrylic, Glass, Other... Tools, Location, By Make/Brand/Manufacturer Name, & Acrylic Tank Repair

Acrylic Aquarium build.      1/20/19
Hi guys/Bob,
<Good morn Mike>
I’ve built a custom (cell cast) aquarium 60”X36”x 24.5” high top and are 1/2” acrylic, side panels are just shy of 3/4” acrylic. Joint gaps before glue are .02”. Glue used is Scigrip 42.(you can’t beat 4000psi) Some small bubble here and there and some crazing. Tank holds water fine. Long side panels bow measured from Center with a two foot level,
<A note here: I'd use a longer level... >
I get a 1/16” gap from left to right at either end of level. From top to bottom I get 1/8” gap at either end of my 24” level. Is this bowing ok?
<Mmm; likely so; considering the thickness of acrylic used here. Are you sure the stand itself is level?>
I get very little bow at the short ends of my tank. I drained half the water and found the bow very similar than when the tank is full.
<Ah, yes; the material is not going to bow itself>
I was planning on running an old Tunze wave box on the tank as part of a stress test to test the seams. Tank panels were laser cut and all lasered edges were shaved off till stress bowing of the panels were relieved.
<Oh! Neat! Not a worry then.>
One of the well known tank manufacturer wanted to make this tank out of 100% 1/2” acrylic. I totally didn’t want that!!!
Thanks for your help.
<Thank you for sharing. Bob Fenner>

Re: Acrylic Aquarium build.     1/21/19
Hi Bob,
The tank isn’t perfectly level but I did make sure there was no twist in the stand before adding water to the tank. I used a high quality level. Accurate to .0005”!
I can certainly use a longer level or straight edge for the 60” but I was using it as a brief reference. I would imagine 18” past my 2ft level at centre would be 1/8-3/16” gap at either end. I can confirm this when I do another water test.
<Yes I would>
I have to ask you again. How comfortable are you with the thickness of acrylic I used, high quality glue, my application method and amount of bowing?
<Am very fine w/ all>
Best regards Bob!
<Cheers, BobF>

Re: Acrylic Aquarium build.       1/30/19
Hi Bob,
<Hey Mike>
How much bulging is too much on the long side at mid height going horizontally (gap at either end of the 60” length on a straight edge?
<Mmm, maybe a half inch... going back to your other dimensions; particularly the 24.5" height. Some acrylic is softer than others... the flexing is not such a big deal (right, define "such"); but bulging rarely indicates a propensity for structural failure>
I’d like to know what the maximum Gap your comfortable with regarding 3/4” thick acrylic. We’ve established 1/8” vertically at Centre.
<That's more than fine mate. I would not worry Re.>
<Welcome. Bob Fenner>

Re: Acrylic Aquarium build.     1/31/19
Thanks Bob!!
<Welcome Mike>
Yea tank is 24.5” high but the 3/4” panels are 23.5” tall alone. That worked in the acrylic calculator on the DYI guys website. I could always cut the tank and make it shorter in height and re-glue the top back on.
<I'd leave all as is>
Thanks so much for your input Bob. It’s a heavy tank going on concrete slab.
<Thank goodness; and hey, could be worse. Think if it were made of glass! >
<And you, BobF>

Bldg. Tanks... using WWM        4/29/15
I have finally got the material to build my gar a good tank. It is 5' by 2' by 2'. My question is, should I brace it?
<Yes.... read here: http://wetwebmedia.com/EuroBracesF.htm
Bob Fenner>
I have never built an aquarium before and need as much help on it as I can get.

mirror as an overflow weir     3/12/12
I love the website and I'm happy that it often shows up in searches on Google.  I have a softy/lps reef tank now and enjoying it very much.  I'm planning a 12"lx13"dx13"h (12" high of water) pico tank to have strictly for SPS corals (my wife loves the colored sticks).
<Hard to do in such small, unstable volumes>
 I will light it with a DIY LED setup (or maybe buy a screw-in fixture), probably 36watts.  I will have an inch or so of sand (crushed coral maybe) and a few pounds of rock.
I plan to have no motile animals unless a few snails, hermits or maybe a small shrimp end up being useful to the biotype (algae growth, etc).  This should help reduce the nutrient issue, and plan on 1-2x weekly 1gallon water changes (with a ~5.5g tank, this is about 20-35% of the water volume).  I will have a false wall a few inches from the back that is 3/4"-1" shorter than the outer walls, this will be a 'weir' overflow to the
back, which will have a small heater and a pump or two (for 'return' and circulation).  the idea is that there will be no equipment at all in the viewable tank.
Now for the question:  I like the idea of making this false wall out of a mirror.  Two reasons: 1. It will help hide the equipment in the back of the cube, 2. It will allow you to easily see the back of the rock and coral formation (and give a sense of extra depth).  The big question is that the material used to make it reflective will be in contact with the water in the back of the tank full-time.  what is it made of?
<Mylar... encased in acrylic... would be my choice>
 is it SPS-safe?
if I got a mirror with a piece of 1/8" glass laminated to the back?  are there any options here?
<I'd not use real mirror... but the acrylic, Siliconed on...>
Thank you!
<Welcome. Bob Fenner>
Re: mirror as an overflow weir
thanks for the super fast advice!  I'll look into the acrylic-encased Mylar for the job.  I do understand the SPS are hard in small volumes, but I'm hoping with 1-2x 25% water changes per week and no bioload that it will be successful.
<Ah, welcome. BobF>

Yet another question, Tank 05/29/2008 Now a day one can find aquariums in all shapes and sizes. The more advanced people can even build their own, though I would live in fear of discovering a water world upon what had been my floor. Though having people who built aquariums for a living build me one sounds nice, if only I was rich. <<Its actually not that hard to build an aquarium, my previous reef, 110 UK Gallon, was hand built by me, and I had never built a tank before>> This range of tank sizes for the same amount of water how ever makes a problem. Fish "A" need "X" amount of water. Just about every body has a idea on how much "X" is, though often the numbers are not the same. Maybe having the same measuring system worldwide would help every one with their numbers, but still it give a good idea that fish "A" want fit into tank "B" because "B" can't hold "X" This bring me at last to my question though I had to ramble on to get to it. Is there some kind of secret magical system out there to determine size of the tank for the size of the fish be on "X" amount of water? I was thinking maybe it might be the fish length times some unknown number, but that would not work unless your tank was a square. Though if you had one system to determine length and another width it might work. A person could get a tank made were the fish could swim the length of their living room, but would have to fold it's self in half to turn around. A lot of tanks are 18" wide but would a 12" fish in a school really like only 18" to turn around in? Just how do you tell when a tank is now to small for the fish that was raise in it? "X" amount of water can only get a person so far and "X" tend to be when the fish is fully grown which can lead to really big tank, very little fish, that might live long enough to be big fish, so long as the filter don't eat them first. <<It does pose an interesting conversation point. in theory. However, as there are that many fish available for consumers / hobbyists to purchase, to me, it does not make a mathematical equation plausible. The tanks we buy, should, if starting from scratch, be purchased based on the stock we want. An example, I want to keep an Paracanthurus hepatus, so, I would go out and buy (or make) a tank suitable. Which, in this case, would be 120 gallons plus (5 or 6 foot preferably). The point is, tank size is all based on the stock, no real need for math to be involved. Just an opinion on the subject of course.>> Oh before I forget thanks for answering my question, it nice to find people out there that don't start heading for the door when I start talking about fish again.... family's can be rather odd at times. One would think verbal information about fish was some kind of new form of torture by the way they act. <<I hope the above helps, regards, A Nixon>>

DIY/Acrylic Thickness For Large Tank 5/14/08 Dear WWM Crew, <Hi Rob> I'm building a large tank and I'd like some advice on the thickness of the acrylic I should use. The tank will have acrylic panels on the front and both sides. The back and bottom will be concrete. I've attached some images for clarity. The dimensions of the sheets are as follows: Front pane: 3000mm x 1500mm or 118" x 59" Side panes: 2000mm x 1500mm or 79" x 59" The water height will be 100mm above the top of the pane, so the water height from the bottom of the pane will be 1600mm or 63". I also plan to use piston type wavemakers so I presume the variable water depth under the peak and trough of the waves will add to the pressure on the panes. I was hoping to be able to use 50mm since this is the largest easily available sheet size. Unfortunately after using Cyro's calculator this seems a little optimistic. The calculator I used is available here: http://www.regalplastics.net/aquarium.htm. The calculator showed that 60mm for the side sheets and 70mm for the front sheet is more appropriate. I'm hoping that their calculator is overly conservative and 50mm will be fine. Based on your experience do you think I'd be able to use 50mm thick acrylic for the front and side panels? I can handle a very small amount of bowing on the viewing panes but I'm not prepared to take the risk of catastrophic failure. <Rob, you should be fine here with a near 2" thickness. I can say that Tenecor manufactures a similar size tank and they use 1 1/4" thick acrylic.> Thanks in advance, <You're welcome. James (Salty Dog)> Rob

Re: DIY/Acrylic Thickness For Large Tank 5/16/08 Thanks for your reply, James. <You're welcome.> Do you think I could get away with 40mm? This would be a little over 1 1/2 inches for a 63 inch water height? <I really do not want to tell you it is OK, I'm no acrylic expert. I was basing my response purely on what size acrylic Tenecor uses for a similar tank. So, if it is OK with them, I'm sure it would be fine with you.> I presume the Tenecor tank you're talking about is the "Ultra Rectangle U1320, 120 x 48 x 60", yes? <Believe so, quite pricey also if I recall it was over $15,000.> My source is http://www.tenecor.com/acrylicaquariumchoices.php. I presume the water height must be around 57" or so with this tank so it seems possible I could use 40mm.  Apart from the price difference in the sheet size, some suppliers only stock up to 40mm here, so hopefully I'll be able to get a more competitive quote. Thanks again in advance, <You're welcome. James (Salty Dog)> Rob

Re: Yellow Tail Fangblenny, Meiacanthus atrodorsalis  4/13/08 Thanks Scott, <Welcome Lawrence.> All good advice as per usual. The boxfish is really happy at the moment, very friendly and watches us as much as we watch him, but I know he'll need larger accommodation in the future. <Yes he will, but these sure are fun fish to watch, some of the goofiest fish I have ever seen!> The plan is to move him in to the Ubertank we have planned, a truly mammoth system hopefully. <Sounds good.> Do you know of a good link or book regarding the construction of large tanks, possibly with block work and fibreglass sides and a single glass/Perspex front? <I know of no such book and have actually started on one (yes Bob, finally!).<<Yay! RMF>> As far as websites, there are a few that can guide you through such a project. Of course WetWebMedia.com has much useful information in this regard throughout the tank building FAQs. Another site worth checking out is the Garf.org DIY pages. This will give you the basics of how to, but the automated calculator calls for too thin of materials for my taste for the larger tanks.> Laurence <Have a good day, Scott V.>

Acrylic aquarium... fabrication. Looking to learn in/from Malaysia, Thailand   5/3/07 Hi Bob, 1. I would like to learn to bond and bend 1 in to 2 in thick 8 ft length acrylic sheet. 2. Is there any colleges in USA or elsewhere I can learn? <Mmm, none that I'm aware... but no doubt there are such...> 3. Is there any books or website I can refer to ? <Ditto> 4. Is there any companies out there who is willing to teach ? <Contact them... likely the closest such "acrylic/Perspex..." Plastic fabricator/dealer in your area is worth calling, contacting re whether they'd take you on...> I am willing to pay for it. Thank you. <What area do you live in? Do use the Net (search tools) and Yellow Page/Phone directories under the word "Plastic" to find companies in your area... There are several places in the U.S. that you might visit re.> Subject : email from Mr. Thanaphon Manavatioeth of Thailand 1. I recently read your email regarding coral reef aquarium. 2. Salt water fish is extremely difficult to maintain, costly too. 2a. Many people failed because of cost and difficulty to maintain. 3. For a start, I would suggest to start with fresh water fish, which is much easier to maintain and low cost. <Good advice!> after you have gain the necessary know-how, than do the salt water fish.4. You mentioned that you have worked with acrylic aquarium before, if you have any experience in bonding and bending 1 in and 2 in thick 8 ft length size ? I would like to learn from you. 5. I am from Malaysia, if necessary we can meet up in Thailand.6. My email address is kimchoo_59@hotmail.com .  Thank you. <Mmm, I will take the risk and post your email addr. here... Am hopeful that someone/s will come forward to assist you. Bob Fenner> Black Aquarium Frames  2/16/07 Hello Crew, I would like to build my own aquarium but I can't seem to find the black framing material. I am constructing an odd size and All-Glass or Glass Cages  does not have what I need. Any suggestions? -Deb <Yes... do contact Oceanic and Perfecto re whether they will supply you (have in years past... though the trade has undergone... what's that polite euphemism? Consolidation... If not available from the aquarium manufacturers, consider fashioning your own... do know that these "frames" are not structural... so yours need not be either... Bob Fenner>

Acrylic fabrication  2/12/07 Hello....I am building some acrylic fish tanks (1/2 in cell cast 36*24*24 full top panel with cut outs) and was wondering what method  you use to heat the acrylic for bending. I would love to be able to use 1/2 inch and bend it. <Mmm... well... you could build/fashion a heat table as we and others have... with an element (electrical) flanked by two cold water pipes (flat)... and a second-time piece and standards for tilting the acrylic panels up to the appropriate angle in time... But I would likely call, use these at a local fabricators rather than build my own for a one time use> Also do you use shims when bonding with the Weldon 3? <Not usually... but a good idea to use gigs or wood clamps at least to hold all in relative place...> I have heard that using small wire shims will raise the panel a SMALL amount. <Yes... too much with thin material (under an inch thick let's say)> This supposedly allows better flow of the solvent. <Mmm... not necessary... the solvent will easily flow/occupy the gap if cut right, fitted closely> You remove them just after applying the solvent and then lightly clamp the panels. <... Uhh... I'd be practicing with some "cut-offs" if I were you... before trying the "real thing" here> I usually have good results not using them but there are a few places on the joint that do not appear to have full contact. <Not good... bad cutting...> The joints do not fail but they are not crystal clear all the way like the store bought tanks.  Looking for any tips you may have <I'd be inserting some corner bracing...> Also how do you start building a tank? <?> I started by lightly clamping the front. back and sides together. I then placed that onto the top panel (upside down) that I had already cut out for access. <Good... this is how I, and our "old" companies used to do... for small/ish systems> I then solvent welded the top and the sides. After that set up I flipped it over and set it onto the bottom panel. I reached through he top panel cut outs and solvent welded the bottom panel. Here area couple pictures of the 90 gal I just made. <Very nice!> I added the back panel to the black top after these pictures were taken sorry for all the questions but I value your advise on this. LOVE this site!!. I am getting ready to build a new 8*24*24 240 gal tank to go in the wall <Sounds like you're ready! Cheers, Bob Fenner>

Re:... acrylic tank white-out seam repair?   2/14/07 Ok so I should get some 1/2 inch wide and 1/2 inch  thick square stock to use as reinforcement along the inside joints? <Yes, I would for sure... Do take a close-look at the square stock... often it is only really square on two sides... the others being convex... Of course you want the truly square faces against the repair> Also I was wondering if it would be safe to router the  edges of the  tank so that they are a bit round and not such a sharp corner. <Yes... as long as the joints themselves are left intact> I was thinking a  1/8 inch  or so. I was prepping the next sheets I am using for the tank I am building now. I used 400 wet sanding to remove any machining marks and make a totally smooth surface to solvent weld. Hoping for some crystal clear welds  :) <Yes... Want to mention (for you and posterity) that you might want to look into a "higher number" Weld-On product (more gel-like)... and perhaps better gear for cutting the sheets... should be flush, not require any sanding...> Thanks again for the help!!
<Welcome. Bob Fenner>

Re: Acrylic fabrication  - 02/15/07 OK I will router the edges some to knock off the corners and I will make sure that the square stock I use as reinforcement is perfectly smooth on  the contact sides.  I was also wondering about a triangular rod that would  fit into the corners.. any ideas on that? <Have used this as well... Will work, yes> The place that I get the acrylic from cuts the panels to my specs but I am sure they are not using a $200 blade either to make the edges finished. <Mmmmm... am surprised the edges aren't more "clean"... Do they have suggestions re sanding them smooth?> The Wet sanding worked awesome. I now have welds that are 99% crystal clear. <Mmm... okay> I took a  2x8 inch x .50 inch scrap and solvent welded another identical piece on top as  in a  "L" shape. I then cut 1.5 inch strips of sand paper and  used it as a guide block for sanding. This worked great for keeping me  square on the edge <Sounds good> I used the #3  because I was under the assumption that it was  the solvent of choice I have read that  the #16 gel was not as strong  and therefore not to be used for actual joints but ok for baffles and such.. I  heard the # 4 was just a tad bit slower in set up/dry time I used a similar  solvent to the #3 about 15 yrs ago when I made my first 240 gal tank. <As an important note here... I met with friend Leng Sy/EcoSystem yesterday... he was down picking up a good quantity of #3... Said that Weld-On has changed formulations in recent years... the number 3 is what most everyone uses on the west coast...> It  held up great but unfortunately was dropped during a move and suffered some  cracks. The place that cut those sheets for me used a blade that did leave a  really level edge on it. <Good> Again, thanks so much for your input and advice. I appreciate the time and effort it takes to do this. Ed <Thank you for the input and clarifications. Much appreciated. BobF> **On a personal note I have owned a Mortgage Company for 18 years so if you have any Mortgage related questions please feel free to ask   :) <And for this!>

Re: Acrylic fab... and fab tools!  2/18/07 OK I went out and bought a nice Delta planer this weekend. <How nice!> I can now clamp the panels together, run them on the  planer and make them all the  exact same size and finish the edges in one move :) This thing is just awesome,  what a time saver. It weighs @200 lbs so it was a bit of a load to get down  in my basement by myself, but I won the battle :) <Oomph!> I built the base of a skimmer I am making for a guy and the joints are just beautiful! <Great> What is your opinion on Chemcast Acrylic? I have read in one place from a very experienced tank builder not to use it for aquarium use. I searched trying to find more info but could not. <Mmm... I have heard similar opinions from folks re this Mexican co. product... though they are (admittedly) one of the largest producers in N. America... I have heard, what I would couch as rumours, that it (as a general stmt.) is "too soft"... that sometimes their sheets are inconsistent in thickness... quality> I hope he is wrong but if not then the 2 tanks  I just built will be reptile tanks I guess. Thanks again Ed
<Good attitude. Thank you for sharing. Bob Fenner>

Aquarium rims   1/27/07 I looked through your search engine but couldn't find an answer.     Do you know some place that sells plastic aquarium rims to the public? <A few of the manufacturers will sell this to the general public... I'd check with Oceanic, Perfecto...> I am re-building an old 70 gallon aq and would like that support on the top and bottom.   <Mmm... more for the assembly process and looks than physical strength...>   If not do you have any other suggestions on how to make one out of something besides wood?   Thanks.   -Steve Balogh <Please see WWM re DIY Glass aquariums, Repair... Bob Fenner>

Skating on Thin Glass  1/23/07 Hi Crew, <Hi Dan, Pufferpunk here> Just a very quick question for you today. I recently purchased a second-hand 72x18x19 aquarium with stand and hood as it was absolutely dirt cheap and is in excellent condition. It's 2 yrs old but has never been used. It is made of 1/4" glass with a 1/2" base. It also has two 9" wide braces. I have done a lot of research on your site and others and seem to be getting mixed opinions whether this glass thickness is going to be too thin. I figure it's best to ask you and be sure rather than fill it up and potentially find out the hard way! <Sounds like you've bought yourself a nice, big reptile tank.  It will not safely hold water, IMO.  ~PP> <<Is on the borderline... but this is likely intended to be a fish tank. RMF>> Thanks!  Dan

Re: Fish Tank Glass Thickness  1/23/07 Thanks for the quick reply. The tank is definitely meant for fish as it already has an in-tank overflow built into it ready to be connected to a sump. I guess all I really need to know is if you think it will break or not when water is added. <I suggest going to fish tank manufacturer's websites, like All Glass &  Perfecto & finding out the thinnest glass those size tanks are sold in.  You might even want to contact those companies & ask them if your tank is OK as is. ~PP> Dan

DIY refugium question  - 1/18/07 Hey guys, I'm helping a friend built a refugium for his 60 gallon. How long  do we have to wait before we can add water and live rock and connect it to the main tank? Thanks again for helping us. <...? What Material are you using here? Glass or acrylic? What kind of sealant was used? Assuming glass and silicon -- I would wait 24 to 48 hours, as long as 72 hours for Acrylic. Hope this helps! -JustinN>
DIY Refugium setup Q -- A follow-up - 1/19/07
Hey Justin, Thanks for the reply, I am using glass and silicone. I have one more quick question. Do I have to use a special solution to clean the refugium after the silicone has cured. Doesn't silicone have a chemical that will leak into the water if not well cured/cleaned before adding water? <No, the only concern here is that you got a silicone without an anti-mildew additive in it. This additive is what is toxic, and if your silicon does not contain it (it is usually packaged as "Kitchen and Bath") then the cure time is all that is necessary. Cheers! -JustinN>

Aquarium building qualifications?  9/9/06 G'day from Down Under, Crew!    <Howdy from Jamaica!>   Greatly admire your work and dedication on making WWM such a fantastic read!    <Thank you>   I've been reading through your many pages and FAQs on tank setup and business issues. There is however one facet that I'm still puzzled about, and that's with regards to qualifications on aquarium construction.    <Mmm... here in the States... pretty much anyone willing to try, and risk being sued (!) for troubles...>   I'm thinking about purchasing a custom made tank from one of the larger pet shops here in Melbourne but am worried about their qualifications on tank building. I'm not really referring to the generic Marine Biology degree but am more curious about how they can come up with the calculated thickness of a 12mm glass pane for a glass/ply tank or the loss in head height for a pump with an additional UV  sterilizer on a by-pass.      It struck me that almost anybody off the street may be involved in tank building, as long as they have 'many years of experience' in this industry or if they can provide a portfolio of previous work. Can any Tom, Dick and Harry accomplish the task as long as they have access to WWM and rip off data from your tables and charts?    <I believe so, yes>   Hence, my simple question after my long-winded intro is; Do you know of a specific course or education program that I could ask of from the builder of my future aquarium as to ensure that he/she is properly qualified?    <Actually... no... am thinking anyone who might try the business would be careful (enough) to not offer shoddy, unsafe merchandise... But have known small-time (local) operators over the years that came in/went out of biz due to tanks coming apart>   Thank you for your kind assistance and apologies if I've gone off-track.   Cheers   Colin <Not at all... good question... Just don't know/have much of a good response. Cheers! Bob Fenner>

Silicone Toxicity/Refugium Lighting - 09/02/06 Hello crew... <<Howdy Mike>> Ok I built a refugium using a used 20 gallon tank. <<Cool!>> I welded acrylic to create: an intake compartment where the skimmer will sit, under-flow to the refugium compartment, over-flow to an activated carbon compartment, overflow to an empty compartment, overflow to last compartment with lower water level (waterfall for gas exchange) where water is heated and returned to main tank.  The tank is divided lengthwise so that the intake/skimming, carbon, empty, and heating compartments sit in the back and the entire front of the tank is the refugium, which once established will conceal the other compartments from view and hopefully make the tank pleasing to the eyes.  The acrylic dividers were welded together with solvent and then siliconed to the glass tank. <<Ok>> Is there a problem with using silicone to join acrylic to glass? <<It's not recommended for structural applications, but in this instance/for this application it's no problem at all>> The tank is working perfectly in my fresh water test runs, but I had heard that this may be a future problem. <<...?>> Also, I ordered live rock and it should get in tomorrow (9/1).  The silicone has been cured for about 48 hours.  Can I use the refugium to cure my rock or will the silicone damage the organisms on the rock? <<It will be fine to use the refugium>> Someone told me I had to wait several days. <<Nope...give the silicone 24-hours and you're good to go>> Do I need to provide light for the rock while curing? <<Is not a necessity...please see here:   http://www.wetwebmedia.com/lrcurefaqs.htm >> My main tank has excellent lighting, but I just have a 38 watt full spectrum florescent for the fuge. <<Depending on what you plan, this will likely be fine...see here: http://www.wetwebmedia.com/refugltgfaqs.htm >>>> Thanks, Mike <<Welcome.  EricR>>

Refugium... glass cut too short   9/2/06 trying to make a 20 gallon long refugium for a oceanic 58 gallon tank. I had some glass cut at a local store and i measured the tank 11.5 inches , I'm short a quarter inch on both sides anything i could use to make up the difference so i can silicone them. <Mmm, no... but if you'd like to salvage this project, you might get by via siliconing strips (two inch or so wide) of quarter inch plate on the short sides. Allowing this to cure (a day) and siliconing to these in turn. Bob Fenner>

Questions, AL tank...   8/12/06 this is going to sound <Not sounding, but looks like... where is your grammar?> like a stupid question or two but let me give it a go. I am building a custom freshwater tank out of an old (but very clean) aluminum  scuba jug, i am using a Fluval 104 filter and plan to put a few 2-3 tiny finish in it. i have a few concerns; 1-the inside of the tank is aluminum, will this cause a problem for the little fishes or do i need to coat it with something such as an epoxy, fiberglass or will just regular spray paint work? <Depends on your water quality... if not too soft/acidic might be fine uncoated/sealed> 2-the volume of the tank is quite small (about 2.25-2.5 gallons) is this acceptable for a few tiny fish or do i need to add a larger "volume tank" to increase this volume and if so how much. <Some small species could be kept here> 3-i would like to attach the Plexiglas front with either aluminum fasteners or possibly brass or stainless steel. the brass one look awesome but since the tank is made of aluminum i would need to install a sacrificial anode in the tank to protect it against corrosion (much like in your water heater at home). will this ruin the little fishes day? <Oh yes> thanks for all the help. <Interesting concept... If it were me, mine, I'd likely coat the entire metal/s surface with an epoxy (over the dissimilar metals and their bond as well, silicone in place the acrylic... Bob Fenner>

Great cut job!

Re: Questions, AL tank...   8/14/06 I am very random when I write emails; it comes from working with huge groups of people at once. <Just me here... about as random in responding> Even my conversations usually end up being thousands of tiny little fragments. Sorry about that. <No worries> That is a great idea; I think that I will put it together with the stainless screws holding in the acrylic. I have already tested with only adhesive for the acrylic and all that I have tested will not work because I still need some compression on the acrylic. Then I will go in through the access in the back and seal the back side of the screws and the aluminum with epoxy. Next time I will use blind screws. <Neat... and that's a fab cutting job... Al 80 tanks are nearly a 1/2" thick... was this done with a plasma tool?> I have plans on building a set of doubles in the future. I will send you a picture of it when finished. <And if I may, I suggest you submit the finished article to the dive magazines (my choice in the west would be Rodale's Scuba Diver)... am sure they'll be interested in seeing your handiwork. Bob Fenner> Thanks so much, Rick Bower

Glass enclosure question for non-fish person   6/10/06 I should start by saying this is for a small animal (chinchilla) enclosure but nobody making cages seems to have a clue about glass enclosures that I've found, or if they do they're certainly not interested in sharing information with some crazed nut who wants to do it himself! (Egads, man! Have you taken leave of your faculties!?!?!) So, here I am, up the proverbial (fecal) estuary with no visible means of propulsion as it were, and I wondered if you chaps might be so kind as to help me. <Will try... after all, "a glass box is a glass box"> I have a question about corners and joinery, if that is the correct term.  I am trying to make an octagon shaped enclosure with the following dimensions: Height: 48 inches Width: 43 inches Essentially, each of the 8 sides will measure 18 inches across by 48 inches high. I know the angles at the joints are 22.5 degrees each but my question is about the strength of the joint itself as opposed to a standard 90 degree joint.  Would you recommend a metal joint brace of some sort for each corner or would you use some other method of adhesion?   <Mmm, nope. The Silastic/Silicone itself, with or even w/o the cutting/joining of glass joints is very strong indeed> Bearing in mind that a chinchilla is basically just a cute rat with a nice fur coat on him who chews like the bloody dickens, I'm tending to shy away from a sealer for fear he'll wind up ingesting it.  Any clues on what to do or who (if not you) I might chat up for answers? <There will be a minimum of material available to this animal on the inside if you run your beads properly. The material is chemically inert once cured...> I've talked to window and glass people but they've all got their own ideas about what to sell me whether it works or not, and I'm running out of time and patience for that lot.  If there is a metal brace that can be used to line the edge of the glass and hold it whilst being fashioned to another piece at a constant angle, <Not necessary... you can build a jig for such, but have build hundreds of such enclosures with just sturdy (strapping type) tape, built in sections/pieces, on-top of the intended bottom... on a level, planar surface. The 100% Silastic/Silicone is "sticky enough" to hold the two piece sections, later joined as four, eight... by itself> could you please enlighten me as to what exactly it might be called so I can re-commence my search for either 32 or 64 feet of it? <No bracing necessary, or desired, other than the tape if you'd like> I apologize for not having a more subject appropriate but after perusing you FAQ section for a bit I figured you chaps might just be of some assistance.  Thank you for taking the time to bother with the likes of one such as I but I didn't know who else to try at this point, so thanks again. Truly. Sincerely, Thomas Mc Leod <Give us a write back if you have further questions Tom. Bob Fenner>

Large Tank Questions and Outcome of Silicone II  5/29/06 Hey guys, wanted to bounce a few plywood tank questions off of ya and provide experience input concerning Silicone II. First things first, I have two large tanks which I recently set back up (long story), I used swimming pool paint which worked VERY well and had no adverse effects on sps or other livestock. Long story short, when I set them back up, I used Silicone II to reseal the corners of the tanks. It has now been 2 months, I am getting consistent trite readings of .025 (Salifert), not high but it should be 0. I am now faced with daunting task of replacing the silicone with Silicone I. (I tried everything including adding live bacteria, carbon, Purigen, all types of stuff, bottom line, at least in my experience is that Silicone II isn't reef safe, live rock is 8 years old) <Yikes...> Now on to the large tank questions. I searched all over, including GARF for info on epoxies. Swimming pool paint with plywood tanks works for several years but ultimately you end up with micro cracks in the paint that need to be patched with silicone or repainted. I am building a tank that would be approximately 1500 gallons, I want to use a reef safe epoxy but I cant locate where to buy Rustoleum or DuPont potable water epoxies, do you guys know of anywhere, or know of any alternative epoxies that might work? <Mmm, I'd look into your local swimming pool supply places here. I have used Nelson/Nelsonite with good results as well as (more pricey) Spar products (intended for the boating industry)> I have also come to the conclusion that since this will be a reef, I am best using glass versus acrylic since acrylic will ultimately get pitted by coralline (I even looked into Polycarbonate but from  what I understand it bows too easily). The glass dimensions would be front panel 96"x30", would 3/4" Starbrite or Starfire glass be thick enough in your experience? <Yes> From what I have read it is reinforced glass, and while pricey, is much stronger As always thanks, Tom <Thank you for sharing Tom. Bob Fenner>

DIY/Aquarium    3/17/06 Hello,  <Hello James, nice name.> I am building a new tank for my marine fish.  It is going to be 3.2  metres (126 inches) long and 1,3 metres wide (51 inches) and in 19mm   glass (0.75 inches).  How high should I go with this pressure of water?  They are saying <Who is they?> I can go 1 metre (39 inches) but I think that could be too high?  What is the ideal height in your opinion?  <If it were me, I'd just follow dimensions of commercially built tanks somewhat close to your size. Then you know you should be safe.  Do keep in mind bracing and glass/acrylic thickness.> Thanks in advance,  <You're welcome.  James (Salty Dog)> James. Fiberglass Use   3/14/06 Hello wet web,  <Hello Mike>    Thank you for your response on my skimmer question. Here is another for you. Would it be a problem if I used fiberglass as sealant instead of cylicone <silicone> or would it be toxic to fish? Is there a certain brand that I have to use or will anything from Lowes or Home Depot work? <What is the sealant going to be used for?>Thanks for the help.  <You're welcome.  James (Salty Dog)    Mike

Re: Fiberglass for sealant... pb?  3/15/06 The fiberglass will be used to seal some plumbing, so water will come in contact with  it. <Either I'm missing something here or I don't see the point in using this stuff.  If this is to be used for sealing threads it will be next to impossible to remove the fittings after it sets up.  Much better to use Teflon plumbing tape.  <James (Salty Dog)>      Mike

Some questions about a plywood tank   3/10/06 Hey crew, excellent job on the site.  I've been reading for 4 nights now and am still forging ahead to learn more.  I am planning on building my own tank and such and was thinking of the plywood type tank since it is the only one in my area that really is cost effective and with the outer stain just looks gorgeous.  The tank won't be too large, 40"Lx20"Hx20"H (about 70 gallons) and I'm wondering what size sump I should incorporate and how I can utilize the sump as a 'fuge at the same time. <Posted on WWM: http://wetwebmedia.com/refugium.htm read through the linked files above...> I'm planning on a FOWLR system by the way.  Is it safe to drill cutouts for overflow boxes on this type of tank or would it be better to utilize my Marineland canister filter to pull the water out and supply the sump and use another pump for the return?   <Better by far to drill...> Any idea how much live sand it would take to put a 1.5" or so coat on the bottom? <Add some, add some more...> I'm planning on putting around 70-100 pounds of live rock in the tank as well to help the bio load even though I am still unsure of the number and type of fish I will get (my wife and sons just want 'colorful', hehe).  The guy at my LFS sold me a SeaClone 100 skimmer for 50 dollars which seemed like a good deal at the time but now I'm not sure if it will be efficient enough or if I'll be able to incorporate it into the sump/'fuge. <Keep reading> Any and all help will be appreciated and thank you again for the wonderful compilation of expertise and data. Best regards, Ed <Please use it. Bob Fenner>

Leaking DIY Plywood Aquarium II - 03/14/06 Hello and thanks for the help!!!!! <<Very welcome.>> I finally completed the tank below with your recommendations and so far the tank has been holding water for nearly 3 weeks with no issues!!! <<Ah, excellent!...am pleased to hear of your success.>> Now I am starting to think about how I want to stock the tank and have a new set of questions for you. <<Ok>> I will probably go with a community FOWLR set up, but I am debating about a marbled cat shark (Atelomycterus macleayi). <<Mmm...>> I have heard conflicting reports on size for this fish ranging from 24 inches to 36 inches.  What size should I expect an adult to achieve? <<According to fishbase.org, this critter reaches a bit more than 27".>> If it's larger than 24 inches I will not get one. <<Though your tank is a large volume (512 gallons), at 30" wide it is almost too "narrow" for this animal.  Do keep this in mind when aquascaping the tank and be sure to leave room for the shark to turn around without "banging" in to things.>> Also I know not to mix cat sharks with large angels but how about pygmy angels? <<Likely will be fine.>> Would the shark be any safer with the smaller angels, or would they just end up being a meal for the shark? <<Though small fish are considered part of the sharks natural diet, some consider it to only go after sick/dying or otherwise distressed fish.>> My LFS tells me this particular shark is safe even with smaller fish as it feeds primarily on crustaceans, but I question that in an aquarium setting. <<Intuitive of you...yes, aquarium life can influence/change behavior...but in this case, I think most fast moving fishes (like pygmy angels) will be able to avoid the shark.>> Please let me know your thoughts.  Thanks again!!! Eric Skikiewicz <<Anytime... EricR>>

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>

DIY Aquarium/Type of Wood   2/26/06 Hi, <Hello Robert> love this site. <Thank you.> Can I use MDF for building a tank or should I use plywood. I intend to build a 300 gallon 24" deep. I know MDF is very dense, and maybe a better choice against bowing?. <Bad idea.  You should use marine grade plywood or furniture grade (both sides good) lined with fiberglass cloth and coat with two part epoxy resin. Thanks for you time. <You're welcome.  James (Salty Dog)>

DIY Aquarium/Re: Type of wood  - 02/27/06 Ok, thanks for the answer, just curious though, why is MDF not good to use? <Here is a link to a test that was performed with MDF and moisture.  http://search.isp.netscape.com/nsisp/boomframe.jsp?query=MDF+wood&page=1&offset=0&result_url=redir%3Fsrc%3Dwebsearch%26requestId%3Df7c3d960c988040c%26clickedItemRank%3D4%26userQuery%3DMDF%2Bwood%26clickedItemURN%3Dhttp%253A%252F%252Fwww.anu.edu.au%252FForestry%252Fwood%252Fmdf%252Ftoc.html%26invocationType%3D-%26fromPage%3DNSISPBoom%26amp%3BampTest%3D1&remove_url=http%3A%2F%2Fwww.anu.edu.au%2FForestry%2Fwood%2Fmdf%2Ftoc.html  Not saying it wouldn't work, just wouldn't be my choice for a large tank as you are planning.  James (Salty Dog)> Thanks

DIY plywood glass hybrid tank  - 02/27/06 This is a follow up to a reader's previous submission on advice on a DIY wooden tank. I am not a WWM member (and have no qualifications to be one), but I have built several wooden tanks before. For what it is worth, here is how I have learned to do it, after making a few of them. I have added some pictures. There is not a lot on the Net or in books on this. I only use 12 mm marine plywood, not because it is waterproof (it is not), but because the wood is smooth on both sides, and the veneers in the interior of the sheet are also free of knots. The bottom of the tank and stand is double thickness. Use fine toothed skill saw blades to cut the wood, and you need know how to use a router. Don't use cheap router bits; they will fail in no time. Always use two pot mixes for the paint. Epoxy resin forms a greasy amine bloom on it; you must wash this off with soap before you put another layer on a dry surface (you can not sand this off). Barbecue scrubbers are best for this, and a degreaser (citrus based). This is a common oversight. Use stainless steel screws when joining wood together, they do not strip. They will not be exposed anyway; they should be countersunk in and filled with epoxy. Do not mix epoxy glue in a pot, it will overheat (can actually burn you), and go solid in no time, mix it in flat trays. You can use steel beams along the length of a tank hidden inside the wood, to add strength and eliminate any need for cross bracing in the middle of a tank. My tank has no bowing at all.  I have integrated the base and the tank into one unit. I lined the tank with 4 mm tempered glass that has a pre-baked black coating on the back. This is normally used in kitchens, and silicone glued this on the interior walls. You must still finish the inside of the tank with epoxy before this, it will not stick to wood, and you may have a small leak somewhere and the wood needs protection. You will need a lot of silicone tubes. Sheath the top edge with epoxy, there will some salt creep here. Make sure there are large ventilation holes on the doors; it can get humid in sump area. The tank is more expensive that a regular glass only tank, do not do this to save money, you will not. It is very strong though, especially after 200 screws plus epoxy holding it all together. The tank holds 250 liters water after displacement (350 before displacement) and the sump holds 100 liters water. For better or worse, that is how I did it. There is nothing in this tank yet, it is still cycling. The sculptures are concrete; the skimmer is a hang on Deltec MCE 600. Its biology is a work in slow progress. Due to New Zealand quarantine regulations, live rock is not available (corals and fish are, and they are also quarantined for three weeks on arrival).  <Mike, thanks for sharing with us.   James (Salty Dog)> Have Fun Mike Lomb

Tank Fabrication   3/3/06 Dear Crew, <Gabe> I have some questions concerning aquarium fabrication. I am constructing a 300 gallon system. This is my first attempt. <Neat! Quite a project> I've had some correspondence with Bob and James, unfortunately those emails were discarded and could not be included. The display tank was made with glass sides and a fiberglass bottom. I filled it with water and left it alone for 24 hours. There were no leaks, but...... other problems and concerns have developed. Fiberglass blisters did form in some spots on the tank bottom. <Trouble...> I'm fairly sure these are manifestations of my impatience through two shortcuts; not sanding the MDF core prior to laminating, and not wetting the MDF surface prior to laminating. With this said, blistering in the fiberglass is a problem that can inevitably occur, even with better laminating practices. This, of coarse, has me re-evaluating the use of a fiberglass bottom. <Very glad to read> Also, there are issues with the silicone adhesion. Air bubbles did form between the glass joints. These range from large bubbles measurable in millimeters, to much smaller bubble clusters that resemble trapped water vapor. These bubbles, depending on location, may occupy from 0 - 95 percent of the surface area in the joints. Most formed after 24 hours of curing and all were completely present by 36 hours of cure time. <Not so much of a worry here. I have adhered glass and acrylic panels to frames with Silastic... with a "whole bunch" of such bubbles... as long as they were not continuous from in- to outside there were no problems with leaking or the viewing panels "slipping"> The joints appeared bubble-free for 24 hours after fabrication aside for some minor air pockets. This has me very puzzled and I need some input on this. Here are the facts.     The glass is un-polished. <Shouldn't be a factor... except with cutting ones hands, arms... watch out here when handling!>     The edges were eased with 120 grit. <No worries>     The edges are very smooth and even with some minor undulations.     The edges are fairly square. <No prob.s>     The glass surfaces to be joined were cleaned with acetone. <Good, what I prefer to use (with adequate ventilation)>     The silicone used was GE Silicone I 100%. <Good product>     The silicone was applied liberally. <Okay>     The silicone was applied immediately prior to each section of glass limiting any surface skinning. <How it's done>     The glass panels were held in place with duck-tape under pressure. <For this sized system, I prefer to "lay the "tank" on the face/panel that is being installed, lay in the Silastic, place (with help) the viewing panel in the nestled Silicone... wait a day or more for curing, tilt the whole thing upright, and trim the excess>     Assembly went almost flawlessly and in a timely manner.     The joints appeared very clear and bubble free for 24 hours. Why did these bubbles form? <Mmm, likely some interaction with "dust" from the contact surface, air trapped there migrating> Is this common? <Yes> Could too much silicone be pressed out of the joints causing this scenario? <Mmm, don't think so> Could acetone cause this to happen? <Not if applied a few minutes plus ahead of applying the Silastic... the Acetone "goes away" quickly through evaporation> What solvents may be recommended for removing silicone, especially from the edges where using a razor may not be so feasible? <Leave it/this> I plan to disassemble the tank and start again. Has anyone heard of using a laminate like Formica for the tank bottom. Formica seems like a logical material as it is waterproof and has excellent adhesion with silicone. I understand that glass would be everyone's first choice, but sometimes I would rather be difficult. Thanks, Gabriel <I want to try expressing my concern, lack of ease (again) here with such materials... they are not made to "put up with" the torsional force of so much water height... I would either fashion a very strong "box" of whatever material (a few times past needed strength) that will not, does not show signs of fatigue (in the least) on filling/testing, or revert back to all-glass or all-acrylic here. Please understand my admonition here... tis nothing personal, but a matter of regard for your safety, liability... This amount of water "tearing", getting loose all at once, or slowly can be a huge risk. Bob Fenner>

Glass thickness   2/23/06 Hi Guys and Gals <Robin> Please put my mind at rest and tell me my specs are ok! My tank size is 2500l x 1200w x 800h. I have used 15mm glass <... about 32" tall and 5/8" thick...> all round and have placed struts as follows. On the base I have 2x lengths 2500lx100w. I also have 4xcross struts evenly spaced left to right. These are also 100mm wide. At the top of the tank I also have the same 2500lx100w struts but my cross struts are 4x 200mm wide as opposed to 100mm. My front and back overlap the side panels by 15mm each side. Here I have also placed 2x cross struts on either side inside this overlap. I hope this makes sense to you ? <I think so> I was told that 15mm was a little on the thin side for a 2400litre tank but I think the support struts will help carry this ok. <Is borderline... the volume of the tank is not the real concern/factor... it's the height. If this has been put together "well", and is placed on a "good" stand (level, planar, strong), you should be okay. I would however, practice/fill it outside and leave for a day to test. Bob Fenner> Please confirm. Thanks a ton for the advice. Ian

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>

Leak in an epoxy/plywood aquarium  - 01/09/2006 Greetings WWM Crew! <Salutations!  Sabrina here, but because of a failing with our mail system, not because I know anything about your situation....  I fear I don't have ANY experience with plywood tanks (not so fond of 'em, myself).  Let me explain....  our webmail system occasionally gives us messages that come unaccompanied by the "tray" that includes our buttons for responding.  It seems my particular system - my laptop using Mozilla - is the only one that accurately provides this "tray".  Therefore, you've got me on the horn today. If I'm unable to help, please try responding with a different email service - hopefully it will come through without a hitch.> I have 3 year old Plywood (coated with Epoxy Paint) and Acrylic viewing panel tank.  Its 8 feet long by 2 feet tall by 2 ½ feet deep (front to back).  It seems that I have developed a leak almost dead center in the back seam (where the back meets the bottom piece of plywood) of the tank. <And here we have the reason I don't like plywood tanks.> Its not a HUGE leak, but it is an almost constant drip.    <Yikes.> Now to discover exactly WHERE this leak was (on the OUTSIDE) of the tank, I had to remove all fish, gravel, water and everything else in the tank.  Then I had to physically MOVE this behemoth so I could look at the backside. <Now you're talking my language.  Oh.  You meant the tank!  My bad.> That's when I found the leak point.        Now I have 2 problems: 1) I have NO clue where the water leak is starting from on the INSIDE of the tank.  Everything LOOKS good, but obviously something is not right. I fear that patching the wrong place will just lead to water rotting my wood from the inside out, so I need to get this thing right the first time. <The wood has already gotten wet - I fear the wood rotting is perhaps an inevitability at this point - but, mind you, I know little to nothing about plywood tanks.> 2) What method should I use to patch this leak??   <I plead ignorance.  I would not attempt a patch.  But again, I reiterate, I know little to nothing....> A) I've considered putting a ¼- ½ layer of Cement to completely cover the bottom of the tank thus filling my problem.  But I don't know if cement will adhere to the epoxy paint I already have on there.   <Neither do I.> B)  I have also considered using some Aquamend by Polymeric Systems Inc to fill the problem area, but once again I would have to FIND the problem area to fix it.   <.... and be confidant the fix would be worth your while.> Can you give me some suggestions??   <That you consider what it will take in your efforts before you begin to weigh the costs of an acrylic replacement (incredibly pricey compared to a plywood construction, I'm sure) against the costs of time, labour, frustration, etcetera.> Either in finding the source of the leak or in coating the entire inside bottom to cover the unfound leak. <For the real answer you seek, please do write back in.  Or, perhaps as Bob posts queries, he might pitch in on this one when it gets posted to the dailies and beyond?> Soren <All the best to you,  -Sabrina>

Acrylic and plywood tank - 12/11/2005 Dear Bob,   I have been reading some of the other posts about large homemade tanks on here and was wondering if you could give me some advice for when it's my turn.  In the future (2-4 years, from what my wife says) I plan on building a 10'x6'x4' tank. <For aesthetic and functional reasons I would limit the height here to a maximum of three feet> The tank will be built in my garage. <Hard to move...> I was planning on using 1 1/2" acrylic with 1" plywood sides and bottom.  There will be a skeleton fame of 4x4's spaced out every 8"on the sides and every 4" on the bottom.  Then the plywood will be screwed onto the 4x4 frames.  The acrylic front panel will rest directly on a 4x4, sealed of course, with 2x4 framing at the edges as well as the top and bottom perimeters.  Hopefully to give structural rigidity.  I live in San Diego so ground movement is of a slight concern.  Do these plans sound Ok.  Since you live here as well, are there other people that I can contact who has something similar that I can associate with.  Thanks for your input, DEREK <I also live in SD and have made such tanks... do feel free to re-contact me, perhaps run your ideas through the folks in the local marine and FW fish clubs... some of the folks in retail (Jim at Aquatic Warehouse, Ron at Octopus' Garden). Bob Fenner>

Re: acrylic and plywood tank  12/17/05 Bob, thanks for the reply.  The reason why I want it in the garage is so it can be turned later down the road when we make the granny flat into our master bed suite. <Ahh... I do hope you have a few strong friends!> I can also install a humidity control if needed.  I currently have a 560 gal that is 3 ft tall.  Although nice I would like it to have one more foot of water column. <Mmm, my/our general "rule of thumb" was that for every foot taller, cost of construction doubles/d> If the acrylic is thicker and braced on all for sides and extra bracing on top is it still really that risky. <I would go with the 1 1/2" thick acrylic and not worry here> I talk to Jim and Ron often but not on this matter yet.  BTW do you know of a place to get the acrylic. <Yes... there are a few... San Diego Plastics is where I'd look first... Ridout Plastics as well... Do look about, and don't be shy re "making an offer">   I am pretty set on the 4 ft height so what thickness do I need, however if it is completely unsafe then I will go with only 3ft.  Also why do some manufactures make tanks taller than 3 ft if its not recommended.   Thanks again.    DEREK <Mmm, solventing/welding the bottom and top on are far stronger, have much greater structural integrity than just "facing" a sheet on to a frame... Bob Fenner>

DIY Refugium and Mixing Materials - 12/07/2005 I have been pouring over the DIY forums for hours but can't find a definitive answer on the best way to glue acrylic sheets as baffles inside a glass aquarium.  <Well, you really should stick to one or the other. Acrylic doesn't stick to glass well and there's a significant chance (more likelihood) that they will eventually separate.> I see several posts that say 100% silicone, and then some that say only use silicone to attach glass to glass. <Yes, 100% silicone, but I recommend using all one type of material.> What would you recommend? <Just what is stated.> Thanks much, Scott <You're welcome. - Josh> 

Glass Thickness - 12/01/05 Dear WetWebMedia crew, I'm having a custom made aquarium built and it will have to hold 500 liters of water. (160 cm X 31.5 cm X 90cm) How thick should the glass be to support this amount of water? <<Firstly...if the person/business building the tank doesn't know, you might be in trouble. That aside...assuming the middle dimension is the tank height (L x H x W), 10mm glass should be sufficient...if the last dimension is the tank height (L x W x H), likely 25mm or greater will be required. EricR>>

Recirculating skimmers, Euro- bracing  11/23/05 Hello Ladies & Gentlemen, <Peter> Thank you for your kind attention. Two quick questions, please.  Are Euro- braced tanks stronger structurally than standard braced tanks? <Good question. I don't know> Or is it strictly a utilitarian/cosmetic preference? Believe it or not (believe it) LFS give conflicting answers. <Heee!> Are recirculating protein skimmers considered more effective than non-recirculating protein skimmers? <Yes> The recirculating seams to offer greater dwell time, but non-recirculating pass higher volumes of water. Which is more effective, please? <Recirculating> Compare for example Euroreef CS8-3 models. Recirculating vs. non recirculating. <Good units...> Thank you for your expertise and valuable time. Peter <There is a dearth of real testing of aquarium gear, but some does exist... though the pet-fish literature is not regularly "picked up" by citation services... One can really only keep reading, communicating on the specialized BB's, attending hobby conferences, and "hope" to run into authors, works re. Bob Fenner> 

Custom aquarium  11/18/05 I was building a floor to wall vi-quarium out of a NEO-ANGLE shower stall. <Neat!> It will have a 5 foot waterfall into an aquarium I have designed but have no idea how to go about building. <Not hard to do... given a few insights... tools and materials> I am a contractor so I am pretty good at building things and figuring them out once I have the basic concept of how to go about doing it. I hope that you can help me with that. The aquarium I'm thinking needs to be acrylic i <I... sigh...> <<Still not finished correcting all, not surprised this is from a contractor.  MH>> am thinking so that its light weight and stronger than glass but I haven't made a definite decision on that. It will ultimately depend on which is easier to work with. The thing that is going to be the hardest is that this aquarium is not a standard rectangle. It will need to have angled cut edges instead of the standard 90 degrees edge to fit together, unless there is a putty or something i can make angled joints with. <Please use your spellchecker...> The dementions <As in Dr.?> of this aquarium are going to be 24 inches tall or deep it will be 10 inches front to back, and the shape will be 19 1/2 inches front panel then it will make a 45 (or near 45) degree turn then a 26 inch front panel then another angled turn (same degrees as the first) going into the last panel which is 19 1/2 inches as well. It sounds confusing but if you look at any neo angle shower stall you will see the 3 sided glass and the shape I am trying to replicate you can find a picture and the blue prints for what I am talking about here: http://www.asbcorp.com/product.cfm?prodid=426.  I am basically trying to fit as tight as possible against the 3 glass walls. My questions are as follows: What material should I use glass or acrylic?  <Either... but if it were me, mine (for my own personal use) I'd go with glass... and Silicone into place> What kind of glass should I use, tempered? <Nope, just float> What kind of acrylic should I use, standard Plexiglas? How thick should the glass be (especially the acrylic to prevent bowing. <Depends on water depth... likely 1/4" will do here if the water is 16-18 " deep maximum> How would I make the correct angled cuts instead of the standard score and break 90 degrees cut? <Can cut acrylic at an angle or even bend, have heat bent... I'd contact Tenecor, other fabricators near you in you go the acrylic route re> are these special cuts even necessary because I saw a strange custom angled glass tank that had this black putty looking stuff that seemed to be holding it together allowing a good seal regardless of the angle cut or angle the joining panel was turned.( in other words you don't need perfect cuts to butt up just right, the putty filled in spots that weren't butted perfect together. What can I use to cut the glass/Plexiglas. Where can I get the materials needed? <... see the Yellow Pages... or the Net re...> What sealer should I use to Finish the corners with?  <Posted... on WWM> As you can see I have many questions, but I have been working on this for years and I have all the answers on how to make fake light weight rocks, a mist system lighting and everything else but the aquarium. I finally have the means to make this dream vi-quarium to some true as soon as I figure this last thing out. Thanks for your time, Matt <Matt... don't send out emails with poor English... Do learn to/use WWM... the indices, search tool... Your answers and more that you need to know are posted there. Please start here: http://www.wetwebmedia.com/diytksfaqs.htm and read the linked files above, where you lead yourself... keeping good notes... Bob Fenner> 
Re: Custom aquarium  11/19/05
HA, Thanks Nice to see you have a sence <Sense> of humor. <Very important...> Sorry about the spelling there. I searched WWM for an hour or 2 before I Emailed you. but didn't find what I was looking for. I suppose I will check again. <Please do. Cheers, Bob Fenner> 

Silicone Curing Question 11/1/05 Greetings From Colorado: <Hello from Kailua-Kona, HI> Dear Mr. Fenner, <Brad> I've just about worn out your book. Is it about time for a new one?? <Always working on...> And, I am among the thousands of people who really make use of your wonderful Web-site - Thank you. I am just finishing this 130 gallon custom bow-front (photo attached). I am late in gluing in the overflows, because the original ones were destroyed in shipping. I have used a GE industrial primer for acrylic on the edges of the overflows after roughing them up with 80 grit sand paper. GE 1200 Series Construction adhesive was used for gluing the overflows in place. Live rock is arriving tomorrow, so I would like to test this tank with fresh water today (after only 30 hours of curing). Do you have any idea if the 1200 series would be cured enough for this test (GE is closed on Sunday). <I think so... if memory serves, 24 hours is called for under most conditions> The thickness of the bead is less than 1/4" except for the bottom inside. Also, do you know if silicone will continue to final cure under water? <Yes, should> I would sure appreciate your opinion, and I promise not to try to hold you responsible for what ever decision I make. Thank you so much,
Brad in Basalt
<Welcome. Bob Fenner> 

Sump water proofing  10/21/05 Aloha, <And you>          Hello, my name is Chris I'm an amateur aquarist in Hawaii. <Am out at our place this month mauka of Kailua-Kona... in Holualoa> I have a 240 gallon aquarium that needs a new sump. I have one octopus, six spiny lobster, one Hawaiian reef lobster, three convict tangs, three yellow tangs, one triggerfish, one stripey, one jack, one barracuda, three sea hares and various other inverts. <Neat... likely all self-caught> I'm running a Mag drive 24 for my return which is also used for circulation as well as two power heads. My filtration consists of two homemade fluidized bed filters, two plastic containers filled with blue bonded filter pads and a finer polishing pad at the bottom for mechanical filtration as well as a gallon or so of carbon which I have water flowing through very slowly and finally two Berlin skimmers. Inside the tank I have live rock, live sand, and its filled with real ocean water. The system has been running four months now and my last check revealed unreadable amounts of ammonia, nitrite, and nitrate. (I'm just proud of my set up, doesn't really have anything to do with my question). Basically the stand I made has left me with little room to work with and most commercial sumps will not fit, I've opted to construct my own. I'm really just curious about polyurethane coating. You know the kind they spray on the beds of trucks... rhino lining etc.. Most importantly if this will leach anything dangerous to aquatic life into the water, and if this type of coating would even hold water on a long term basis without cracking or delaminating from the sump walls. <This material... the sprayed-on type is toxic for quite a while... not really suitable for underwater use... there are many other better choices> I have already contacted the company with regards to these questions. Although they told me their linings will not crack and would not release any harmful chemicals into the water I really wanted to get a second opinion on this since this really isn't the normal applications these people deal with. <Take a whiff about the area where they're applied... check the rigs the folks wear while applying...> I already have a sump I made in use, I coated it in epoxy that I got from aquaticeco.com. It doesn't work well, It has repeatedly cracked time and time again even though I measured the ratios carefully and followed their directions to a tee. On the other hand, acrylic is pretty expensive in comparison to polyurethane coating. This is why I'm exploring other options. Sorry if you guys covered this topic already, I did check but didn't see any info on this subject. Anyway thanks in advance for any advice given and wanted to mention my collection habits. I live right next to the beach and catch all my tank occupants myself. I typically keep them six months or so until I get bored of looking at them, then I release them back into the wild. Am I the only person that does this? <Mmm, nope... you've got lots of company> I don't know but works pretty well for me and is so much more fun to get out into the water and catch them yourself! Anyway, great site, the best place to find info. Thanks again. <I would look into fashioning your custom sump out of "used" glass... a lot of glass places re-sell this... quarter inch/triple-strength will do... you/they can easily cut, drill if you like, and not hard to Silicone together... A hu'i ho! Bob Fenner> Mahalo nui loa  -Chris

Aluminum and Saltwater 1016/05 Hi, I read on one of your replies that aluminum was not compatible with a saltwater aquarium (i.e. as a support above the aquarium for a light). Is this because the aluminum is toxic to the fish or because the salt corrosion will quickly deteriorate the aluminum?  <In my opinion, aluminum is fine to use outside of the aquarium and away from water contact. In fact, many commercial lighting fixtures incorporate aluminum. However, contact with salt water will corrode aluminum and aluminum can dissolve into the water and is toxic.> Also, my aquarium is a 40 gallon FOWLR tank that is only 14" deep and 40" long, and I would like to add an anemone (LT or Sebae) Would a 250w Metal Halide Lamp 6" above the water, along with my 65w 50/50 PC light, be overkill? Thanks for your help, Dustin  <I would not use more than 175w MH in such a shallow tank. In fact, although I almost recommend halides for anemones, one or two additional PC's would probably do fine in such a shallow tank. Best Regards. AdamC.>

I Was Told You Were the Ones to Ask... About Silicone 10/12/05 Regular 100% silicone and aquarium 100% silicone. <<Sure, why not?>> As long as it isn't mildew resistant, is it safe to use in the aquarium? <<Yes, it is. There are other additives that may make a silicone unsuitable, anything that is "resistant" to growth of life of any form would count. Barring that, though, the answer is an unequivocal yes.>> I call the manufacturer and they state that they are different but can not tell me how they differ. Is this just a ploy to make more money out of us? <<Or a ploy to show us how poorly trained their Customer Service Reps are.>> Why does aquarium silicone say only use up to 30 gallons? <<WHAT? You can only use silicone in aquaria UP TO 30 gallons? Woops! I guess that 120 I worked on all those years ago is doomed.>> Is it only to prevent them from being sued? <<You would have to consult an attorney to make that determination.>> Is there a better brand than another? <<Not in my experience.>> Thank you for your time and I hope to hear from you soon. Sincerely, Mike <<Essentially what you need to know is this - is it pure silicone? 100% would be the indication you need to look for. I don't think brand matters, but for me price DOES. I have repaired many a tank, and used what was available at hardware stores with no bad results (other than my first couple of tries).  As for what the manufacturer has to say, something tells me that the CSRs would not be well-versed, and your statements support this. If they're different (from..?), then should they not be able to tell you how or why? If not, then they're not so different. Go to Home Depot, Lowe's (not Meek's, we hate Meek's), wherever, get 100%, and you should be golden. Marina>> 

Varathane/s, seawater 10/10/05 Hopefully you can help me.  I am doing a glass installation for a local restaurant, for their 200 gallon salt water tank and want to know if I placed a piece of glass with a coat of cured Varathane would the salt water eventually eat through the Varathane?  Any comments would be appreciated. Chris Windsor Phatty glassworks inc. <Will take a good long while... years, if ever. Bob Fenner> 

DIY glass only aquarium w/Euro bracing  9/24/05 I am planning on building a glass only aquarium 72"L X 30"W X 29H.   I would like your opinion on the following questions if your so inclined. Thank you in advance for your valuable insight. <Glad to share> Would you recommend Euro bracing on the top of the front, back, side's or 1" from top inside the tank? <Euro... more attractive, stronger... easier to work on, light...> If inside, would you overlap or have the braces all the same level, if overlapped which on top vs. which on bottom? <Front, back on top, sides below> What thickness of glass for braces and what width of braces? <At least 3/8", 1/2" better>   If I could get braces tempered vs. float at no extra charge would that make any difference? <Mmm, a little> Would you recommend bracing at the bottom of the tank, if so what width of glass used? <Would not, don't recommend> How would that work with silicone (silicone interior bead first, cure, then install the bottom bracing with more silicone? <Yes, if used>   Or don't do an interior bead and just put the bottom braces in with silicone all points of glass contact?) <Bob Fenner>
Re: DIY glass only aquarium w/euro bracing  9/27/05
Thank you for the response.  I have a couple of follow-up questions. If I understood the response correctly, the recommendation was to put glass bracing on the top edge of the front/back panels of glass and then have bracing for the sides just under the front/back bracing flush with the top edge side panels vs. putting all the perimeter bracing 1" down from the top edge of the tank/all even (no overlapping)? <Yes> What silicone (brand-if possible) would you recommend for a DIY glass only aquarium of this size (225+gallons)? <Brand doesn't matter... just that it's 100% Silicone... no mildewcides, other additives> You did not recommend doing any interior bracing at the bottom of the tank like Glasscages does on their tanks.  What are the reasons for not doing this vs. reasons for doing it, in your opinion? <Not necessary... "more trouble than it's worth"> Again, thank you for your patience and sharing your knowledge! <Glad to do so. Bob Fenner>

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

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