FAQs on Acrylic Aquarium Repair and Modifications 1 Related Articles: Aquarium Repair,  Related FAQs: Acrylic Repair 2, & FAQs on Acrylic: Design, Scratches & Crazing, Leaks, Drilling/Cutting, Construction, Solvents, & Glass A quarium Repair, & DIY Gear 1, DIY Gear 2, Tanks, Stands, Covers, Custom Aquariums, Stands, Covers...,

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Acrylic tank repair question 8/1/05 Hello, I have a question. I am looking to buy a 300 gal sea clear tank. I found a used one locally that has only been set up for 1 year. Selling price $ 400.00.  <Wow!  What a steal!> Here is the catch. It has a .5 x1.5 inch separation in the front panel where it meets the side. <Darn! There is always a catch!  And this one doesn't sound good.> It is not leaking and was like this with no change for 3 months while the owner upgraded to a larger tank. The tank is empty and has been so for 2 weeks. Can this tank be repaired? I don't know where the line is for safely repairing such a large tank (don't really need a swimming pool in my room.) Would be a great deal as my two angels have out grown their home now. I want to make a smart decision with this not only for me but also for the angels, as I don't want to see them surfing the carpet. Any input would be greatly appreciated.  Addicted to your site, Erik Lobe  <This could be repaired by a qualified acrylic shop, but most would probably not want the liability.  It is probably not likely that the tank will fail.  Unfortunately, if it does fail, it probably will not develop a leak... it will fail catastrophically.  As a long shot, you may want to contact Sea Clear and see if they will honor a warranty on the tank if you buy it.  You might be able to buy the questionable tank and get it replaced with a brand new one.  Be sure to get documentation of the original sale from whoever you are buying it from.  Best Regards.  AdamC.> Acrylic Tank Mods Gone Wild 7/21/05 Dear WWM Acrylic Tank Mod Guru : <Mmm, must be all the methacrylate stains on my clothes, the absence of nasal hair...> I think I know the answer to this question already (don't do it!), but here it goes: I have a 135 gal acrylic tank, 72" long, 24" tall and 18" front to back, 3/8" thick, made by TruVu. I want to cut the top completely out (!) and brace around it with very strong wood and steel, kind of like a picture frame if you were to look at it from the top down. This brace would be an integral part of the stand and canopy I am making. I've searched WWM for questions and FAQs on this but can't locate any. Any input is appreciated : if you say don't do it under any circumstances, please enlighten me as to why. thanks, SLC <I wouldn't do this... surprised? You might router out most all the current top... leave a good four inches around the perimeter and the same for the material across the top... but the top is an integral part of the whole structure... and won't be replaced with a frame on the outside. Bob Fenner>

Ready to raise the white flag... scratched acrylic tank 7/19/05 Hey guys,     I have a 65 gal. acrylic tank that I bought used.  When I bought it, I was under the impression that scratches are relatively easy  to remove, as it says on your and every other site around. <Uhh, not easy to remove. For my part, I apologize if WWM has left/given you this impression> I tried using a  Craftics 20/20 scratch remover and polish kit and had no such  luck. Sad to say the tank is now even more scratched than it was before.  Furthermore, the thickened acrylic cement that North Coast Marines  recommended to fill in a small gauge actually made the tank  worse. If acrylic scratches are easy to remove, what am I missing   here? <Nothing... just lots of labor, possibly (yes) power tools>    I spoke with a professional reglazer who wants  almost as much as I paid for the tank to reglaze it. Between this and  the fact that the equipment I got with the tank doesn't work right and  isn't even exactly what I need-- and that is completely and totally  entirely my fault--I am ready to throw in the towel. I'd like to keep  going, but I just can't afford to absorb this kind of a loss and still  pay for all the other equipment I need. I did a lot of homework before I  bought anything but apparently not enough.     I'm not holding out much hope, but is there some  way to fix this without sinking several hundred more dollars into it? I have a  funny feeling this is the end, but with an answer to this question, I can  at least say I've exhausted every option.  I want to thank you guys  for the help you've provided me with. You've all really been great.   Thanks again, Marianne <Mmm, I'd hold onto this tank... use it for "back-up", maybe mixing, storing water... possibly as a sump/refugium for a large/r system down the road. Bob Fenner> How to unstick acrylic from plywood 7/18/05 Hi! I have just finished the building of an acrylic aquarium and as I was putting solvent cement <Not a cement, just a solvent... melts the material together> in the bottom joints from outside the tank, it ran and now the aquarium has stuck with some plywood pieces I used to support the tank from below it. What could I do to unstick them? Thanks. Giannis <Unstick your sentences with spaces... and use (gingerly) putty-knife et al. hand tools to remove the wood... is going to be ugly where all were joined... can be sanded, buffed... Bob Fenner>

(Damaged) Acrylic tank assessment 7/4/05 I am sorry this is such a long post.  I just don't know what exactly is pertinent information, so when you know enough just stop reading.  Reading the posts made me think really hard, and try to be perhaps too observant.  I posted here because you seemed to know a lot about tank integrity. <Okay> I brought home a free acrylic (I think, are there other plastics for tanks?) <Mmm, really only very small ones... acrylic/s have many names, are about all of the same composition> tank today.  It is a TruVu brand, 16 deep 18 wide 60 long.  There are cracks in the top and I don't know the owner (neighbor of an ex-boyfreind), so I can't get the history of the tank. It looks like it belonged to a fraternity (stickers and spray-paint and graffiti).  My ex- did say he was told it doesn't leak. <Actual cracks or just crazing? Can you feel breaks in the material? These are indicative of cracking> I am afraid it will fail. I am not concerned about a slow failure, I am afraid that some of the cracks will just split with no warning after the tank is in use some time.  I also see what I think is some crazing. <Ah, I see> I haven't filled the tank to test it because I wonder if I should repair it first.  The link to the repair story is broken, so I couldn't read it. <Unfortunately there is no such piece... just haven't gotten around to writing it...>   If there is a quick easy fix that may hold this tank together, I will do that first. <It may be that the cracks can just be ignored (fill this tank outside and see how it does), otherwise, the solvent used to weld the tank panels together may be used to anneal the cracked portions (call, write TruVu re Weld-On...). At worst, another panel (thin) of the same size, cut-outs may be solvented to the top/cracked one> CRACKS: These may have been produced by heat, as I read in other posts.  My reasons for thinking so are that the top of the tank is warped, and there is a small area of the top that looks like it may be air bubbles. Does acrylic "Boil" from heat?  Also, the edges of the cracks are warped and do not match each other. <Warping is common... these tanks bend quite a bit with use/time... boiling is very bad> If the cracks were caused by heat, might the tank be compromised to the point that it will fail, because the top is an important structural member? <Doubtful, but a possibility> My reasons for thinking it is not heat is  I do not see any blackening or discoloration.  Also, one crack actually extends down the side of the tank about an inch.  Could this crack be from an impact? <Yes, most likely... am starting to have glimpses of "Animal House"> I haven't filled the tank to test it because I wonder if I should repair it first.  The link to the repair story is broken, so I couldn't read it.  If there is a quick easy fix that may hold this tank together, I will do that first. There are four cracks in the top of the aquarium, they all run from a corner of the large cut out to the side of the aquarium. <These are best repaired per above> The two in the back run from the side cutout to the 1-1/4 diameter hole, to the back of the tank.  One CONTINUES down the side of the tank about an inch, this portion of the crack is not perpendicular, but actually at an oblique angle to the tanks surface.    <Also best repaired> The tank top has two rectangular cut-outs, two smaller rectangular cutouts, six 1/4"D circular holes, and 2 circular holes about 1-1/4 "D.  One of the 1-1/4 inch holes is not really circular, it looks as if a smaller hole was drilled off center of the larger one, however the edges are nice and smooth, so I don't know if these holes were homemade, or poor quality control of the manufacturer.  But the crack is not located near this bump. CRAZING: It is a really sunny day and I noticed when looking obliquely at the tank outside that there was a glittery sheen inside the acrylic.  It seemed to be pretty uniform throughout the back surface of the aquarium, and I did not see any direction to it, just little spots of glitter.  I could not see them on the other sides of the aquarium, but this could be because I did not turn the tank to the same angle.  I suspect that it is crazing.  (If not, what could it be?) <Likely crazing... though could be marks from solvent, local pressure or heat stress>   I cannot see it at all when the aquarium is viewed straight on.  And I don't think I could see it in indoor lighting.  Is a certain amount of crazing a normal occurrence?  Does it happen in every tank? <Is common> USE: When I first saw the tank, I thought that it wasn't very useful for a display tank.  Now I am thinking that it actually would look pretty funky as a type of urban  community tank.  What do you think of this idea? Thank you, Mary <If you have the time, interest, worth trying to effect a repair. Bob Fenner>

Re: Acrylic tank assessment 7/6/05 Thank you for your reply.  I was unsure about how to weld the cracks closed.  The edges don't line up, and in some cases, the irregularities of the edges get in the way of realigning the acrylic. I took the tank into TAP plastics today.  They suggested that I drill a small hole at the end of the crack before I weld.  This will relieve any stress at that point from the misalignment. <Interesting> This makes sense. (Lucky that all the cracks end one inch from the top.) It is consistent with the reason that larger diameter corners are stronger, the stress is distributed over a larger area.   <Yes> The weld-on #16 cost $3.05.  The piece of scrap would have been $1, but he threw it in for free.  Must have felt sorry for me, trying to save such a pitiful tank. He should only see my car! LOL! <Likely> He thought  the warp on the cross member would not affect its strength, and that I don't need to reinforce it. <Okay> He had no idea about the crazing unless it was a solvent.  I suppose its possible the gut tried cleaning it with something weird.  But I really don't think so, it is so evenly distributed.   <Is just "stress" over time mainly> I just wanted to share with you the idea of drilling.   Wow a 75 gallon tank for $3.05!   I'll let you know how things go with my experiment. <I'd appreciate this> I will drill the holes, wash the tank (soap and water he said) <Mmm, no... avoid soaps, detergents... toxic to aquatic life, hard to remove, leave a film... water and vinegar, possibly straight vinegar (white) for "scale"...> and weld a piece of scrap over each crack.  I am toying with the idea of welding an acrylic divider in the middle to compartmentalize it into two tanks, but I haven't decided yet. <Mmm, worth considering... but hard to change later> I would prefer a removable divider, but since the acrylic will flex, I don't know how I could do this. <There are commercially made dividers, but these are a bit flimsy for this sort of tank> Right now I really could use smaller tanks. Well its time to stop blathering, and see if this idea will hold water! Mary <Real good. Bob Fenner>

Help!  Acrylic Tank Leaking  07/02/05 Hello All! <Hello Tammy> Have been rabidly searching your site (lots of great information here) for about 45 minutes.   I've found a few suggestions to the problem I'm having, but was still a bit fuzzy on the execution.  (one recommended using dowels) The short short version is this:   I have a 110 gallon acrylic tank.   Used for Saltwater.  It is only about 4 years old.   I bought it new.    It has only been moved once since setup - I emptied it entirely and had it moved by pro's.     It has been in this apartment for 18 months without incident.   Tonight I decided it was time for the water change and drained off about 30 gallons.   The front has always tended to bow - but I was assured by the folks at the store that this was Ok.  I suspect something about the weight change made a seam leak - because all of the sudden I had a steady drip-drip-drip in 4 places under my tank.   (anywhere the stand was drilled or even seamed it leaked through)   And before I got the wild idea to try and improve the water quality - there was no leak.  (I'd been under the tank changing the filter pad and carbon in the sump first - so I'm certain of the "no leak" report).   So Yikes!   So after deciding that all future tank work should be done during normal business hours, I flipped over some Rubbermaid bins, wiped them out - and started transferring water from the tank and the fish.   I now have an upside-down playpen over the bin safeguarding the fish from my three inquisitive cats and 3lb dog.     I've got the air and heater running in their bin, so I think they're Ok for now - though certainly not liking the close quarters. Where should I start?  Are acrylic tanks typically warranted?    Do you expect I'll get anything other than a "good luck" if I phone the store?   I know I'll need to scrub out the tank now - anything that you would recommend to make sure that it's completely clean for repair?   Usually I just use my scrubby on a stick and lots of elbow grease...   but since I have the chance to take it down and really go to town on it now - didn't know if you'd recommend something.    Once I've got it clean - Where do I begin to look for help locally?  I believe the leak is in the bottom seams because I got down to less than 5 inches of water and still kept dripping.   Is there something I can do myself?  I really hadn't budgeted for a tank replacement - and I'm afraid this is my first leak.   The fact that I'm on the 3rd floor and got thru the whole incident without leaking onto the folks downstairs has me reasonably confident that I could follow DIY instructions should you have any for me....  :)   Also - I'm a little worried that the leaking could damage the structural integrity of the stand...  Is that being over-cautious?  Or do I have more problems?   My father will come over tomorrow and help me lift the tank down for cleaning and I'll get a better view.   Maybe could put the hairdryer on anything still damp? Thank you SO Much in advance for your help!   And Happy 4th of July! Tammy <Tammy, you need to start at the store where you bought it.  Most tanks have at least a five year warranty.  At the same time, email the tank manufacturer about the leak problem.  Most will repair or even send a new one upon receipt of the defective tank.  James (Salty Dog)><<RMF would actually start by filling the tank up outside... with newspaper under it, trying to see if it is actually the tank itself leaking... very likely it his a hang-on device instead.>>

Re: Help!  Acrylic Tank Leaking Hi Salty! <Hello Redhead> Yeah, well you would think they would stand behind the goods, but the store where I  bought the tank has changed hands - and the new owner indicated that he thinks that the guy that they bought it from was hiring local acrylic shops to build tanks - as opposed to selling tanks from national manufacturers.   The guy was a little dodgy as far as when I would mention looking for my warrantee paperwork, he would just say that he was sure whomever made the tank was certainly out of business.   (which I loosely translated into - I'm not honoring a warrantee?)   Then the guy sat and wanted to sell me a new tank, new stand, and then he tried to flirt.   No game either.  Don't get me started.   I considered telling him that I was flattered, but that I was in a relationship and that my boyfriend was an attorney - loosely translated, You'd better honor my warrantee or I'll sue cause I have free legal.   LOL!  <I'm thinking when a store is sold the new owner isn't responsible to honor any warranties, especially since he didn't make any money on it.>   But I really didn't want to continue the conversation.   Just awful.   Instead of staying on point about my tank, kept talking about what a pretty redhead I am - (my hair is DARK Brown)   Doh!  Lousy service and just no game.  :)  Ugh. My tank is a 110 gallon - measures 48 inches long, and 18 inches wide front to back, and 30 inches tall.   It doesn't look like Tenecor makes a standard tank with those dimensions.   Oh!  And Thanks for the tip on the self drill -vs.- ordered drilled.  Important Safety Tip. Now if eBay is a marker of what's out there - the folks making tanks like mine brag that they're using the 1/2 inch - not that crap 3/8 that a lot of people try to get by with.   (dunno if that's true - that people use the 3/8, that is) Tenecor does show a 140 tall: This model features bent (seamless) front corners. Includes a clear acrylic top with filter slots, access hole(s) and matching lid(s). Dimensions are 60"L x 18"W x 30"H Price: $913.00 While I can't find any documentation on their site as to the thickness of the acrylic, I did find a posting on another site talking about the thickness of acrylic to be used...  I've included the post content below, but the gent says that his company uses 1/2 inch thick acrylic for tanks up to 30 inches tall and 600 gallons.  He also mentions recommended/Ok "bow" measurements.  What to expect with glass and acrylic.   Dunno if it's correct - but thought I'd pass it along as well in case your interested. Tomorrow I plan on calling my LFS that I trust - and then calling their suggestion for an acrylic shop.   I'll pass along the prices and info that I get in case it's ever of any use to you or yours.   :) <If you don't live in a big town it may be difficult to find an acrylic shop willing to build an aquarium and guarantee it for a reasonable amount of time.  Keep in mind if you are or will be keeping corals, the deeper the tank the more wattage you are going to require.  James (Salty Dog)> Thanks again & Happy 4th! Tammy

- Acrylic Tank Modifications - Hi guys, I purchased a used acrylic Tenecor 180 gal.  RR tank, drilled for a closed loop and overflow mounted outside the tank.  Sweet configuration (and in great shape).  The top is made of 1/2" acrylic and has 3 cutouts.  I have seen acrylic tanks with Euro Bracing and I like the open access for the lights and working in the tank.  My question is:  If I cut the two braces between the cutouts, do you think the remaining acrylic would act as a Euro Brace and support the load without bowing and cracking the tank? <I'd be cautious. You would likely need to add additional bracing to create a true "Euro Brace". Given that I've only ever seen this type of bracing on glass tanks, I'd be hesitant to tell you this will work on an acrylic tank.> <<RMF would NOT do this>>  The tank measures 72" x 24" x 24". The remaining border would measure 6" wide from front to back (left & right sides) and 4" wide side to side (across the front and back), one solid piece of 1/2" acrylic (or do you think the 1/2" needs to be thicker?).   I realize there are no guarantees on opinions, but I really hope this could work.  The Euro Braced tanks I looked at had 4" borders all the way around. <Of what thickness material on what size tank? Given the length of your tank, the center brace helps stop the center of the tank from bowing, and without this brace I think you might see not only a noticeable bow in your tank but the remaining bracing would also bow and crack. Would for certain test out in the driveway first before adding anything you care about.> Waiting for your opinion with saw in hand...... Scott B. <Cheers, J -- >

Acrylic seam is separating Nice web site! I have an 18 months old 190 gallon thriving  reef tank, 6Lx2Wx2H acrylic.  The top seam, both front and back, is separating in several areas (the side seams are fine). <Yeeikes!>   My wife and I had recently moved and the tank had to be moved and set up several times within a 5 month period.  This was probably the catalyst for my current problem.   I tried injecting weld-on #4 into the gaps with no luck.  I have read (on-line) that by trying to re-bond a seam will only weaken the existing bond.   <Possibly> Whether this is true or not is probably not important at this point, though it does mar the surface when the stuff drips down the front of your tank...very nauseating, as I now have a small bow (12 inches) in the back and a leak in the front.   I went down to my local plastics supply store and discussed the problem with them.  We decided that by bonding a 4 inch wide piece of 1/4 inch acrylic bent at 90 degrees to the front and back of the top seams would be the best solution.  Since the bent pieces of acrylic will have a small radius on the inner side, it was suggested that a product like weld-on #13 be applied to the gap caused by this radius.   <Interesting...> Hopefully you have a good mental picture of what I am describing. As I am writing this, I realized that the outer edge of my tank forms a sharp 90 degree angle and would need to be rounded off in order to accommodate the bent piece being bonded to it.  Round over sharp is not a compatible fit.  Soooo... I guess I'll start my questions off with this one:   What is the best way to "cleanly" round off the top edge since I don't own a router and would not trust myself to use one on my tank. <Borrow or buy a router> Can weld-on #13, or a similar product, be used to bond acrylic?  If not, what can I use and how can I avoid a mess?  I am afraid that #4 dripping down the front of my tank will cause me to go #2. <Mmm, I would use the "thickest" (most gel-like) acrylic weld-solvent that you can find> It seems that I also need to seal the tank seams from the inside as well.  How can I best prepare the area to be sealed and is weld-on #13 (or similar) the best product to use?  Small pieces of coralline algae and salt deposits have accumulated in these exposed areas. <Is the best, the surfaces need to be absolutely clean and dry> Are there similar products to weld-on? <Not generally available to the consumer> Finally, is there a better approach to this problem.  A new tank is not an option. <Might I ask who made this tank originally? Have you contacted them? Have you considered just cutting, attaching square (on two sides) acrylic doweling in all corner/joints? Won't take out the bowing (likely nothing will), but is the best shot at stopping this tank from coming apart)> The good news is that the area of concern is limited to the top of the tank (so far).  Our corals and fish can be no healthier, my wife is a very good marine and freshwater aquarist (sp.) and because of this, I get to believe I am as well. I would really appreciate any help or advice you can offer.  I am picking up the supplies mentioned above today but will hold off with any repairs until you respond... no pressure intended... we have clamps holding things together. Thanks, Jim <Jim, have someone or folks from the "plastics supply" come by and look at your project... they may have clamps, other ideas to help you here. Bob Fenner>  

Acrylic Tank repair... Hi    How are you? I have a question...I just received a used acrylic tank from a friend of mines who was moving. Really nice tank and everything. But it has a lot of scratches... are there any products you can personally recommend that would help me cover the scratches?                     Thanks,                      Jason M. <Yep... posted on WWM... go read there. Bob Fenner>

Appropriate acrylic adhesive for reef tank Hello, <Hi there> I purchased an adhesive (Devcon Plastic Welder) for my DIY skimmer and I have a quick question regarding any problems with this adhesive.  Will this adhesive leach any harmful chemicals after it has cured 24 hours?  Any input will greatly be appreciated.  Thank you. David <No worries... their MSDS: http://www.tapplastics.com/uploads/pdf/MSDS%20Devcon%20Plastic%20Welder.pdf Once cured there is none left... not a glue... but a solvent. Bob Fenner> Acrylic Questions 3/30/05 You guys have been great so far (in the FAQ's an in responding to me). I have two questions about acrylic.  <Glad you have benefited!> 1) I bought a 120 gallon Tenecor pentagon corner acrylic tank, stand and canopy setup from someone. The overflow tower is 4" shorter than the height of the tank. Don't I want the tower to extend to the top so I can avoid an unattractive water line 4" below the canopy? What do I need to do to extend the tower to the top? I assume I will somehow bond acrylic over the current slits and make new slits at the top of the extended tower. Since it's not an area that will bear much weight, should I just use silicone? I'd like it to look decent. The tower is black, but I don't mind clear acrylic extending upward.  <If you can, I would ask the previous owner about this. Some tanks come with adjustable "Dams" that allow the user to adjust the water level. Look for a screw hole in the overflow as a clue that such a device may have been included. Even if it isn't bearing weight, silicone is a very poor adhesive for acrylic. A small tube of Weld-on #13 is very inexpensive and nice to have on hand for DIY projects. Every major city has an acrylic supplier, and most have a "drop bin" where you can buy assorted small pieces for bargain prices. Be careful not to make it too high to avoid spills!> 2) The canopy has 4 small acrylic pieces bonded to the underside for lighting, but the lighting I need to do doesn't fit the slit shape and they are 1/2" thick (two 1/4" pieces, I think). I can't fit my lighting in there without the surface being flush. Is there any easy or possible way to remove these pieces?  <You will have to do this very carefully. The solvent bonds between acrylic pieces can be stronger than the material itself, and there is a great deal of risk of breaking the canopy. Home Depot and other hardware stores have special "flush cut" saws. An El-Cheapo one is less than $10 and will allow you to cleanly saw off the tabs without risking cracking the canopy.> Any help would be GREATLY appreciated. My setup is on hold until I figure this out. Peace, Clint  <Good luck! AdamC.>

Acrylic questions part 2 3/31/05 Thanks! I'll try the flush cut saw. Does the Weld-on seal as well? The reason I ask is that my tower extension pieces aren't completely perfect. Should I bond it with Weld-on and seal it with silicone? Thanks! Clint  <IMO, Silicone has no place for bonding or sealing acrylic. It just doesn't adhere well. Weld-On #13 will bond as well as fill and seal small gaps. If you try to fill large spaces (greater than about 1/8"), bubbles will form, making a weak unsightly joint. In order to avoid this, you can fill larger gaps by applying the #13 in several light layers. Just a warning... Although Weld-On #13 will work great for the application you described, is meant for "hobby" type applications and should never be used for joints that need to hold much pressure. The pros that assemble sumps, tanks, etc., use #3, which forms extremely strong bonds but since it is watery thin, it requires perfectly machined joints. Best Regards. AdamC.>

Stocking 75 gallon Marine System & Covering Unwanted Holes Hi WWM Guys, <Hello Spencer> I have a 75 gal with live rock and a varied number of snails that I got for algae control as per some articles I read at WWM. My abalone and top crown snails died for some reason but the rest seem to be doing fine. I have some hair algae growing on my live rock but nobody seems to want to eat it. I'm thinking about getting a lawnmower blenny or a black Sailfin blenny to finish up the rest of the algae. Which is going to do better? <The Lawnmower> I prefer the looks of the Black. I also have read article about hermit crabs (scarlet or blue legged) and some guys think they eat algae like crazy and some thing they are a waste. What is the consensus opinion? <Don't think there is one> One last question, I have only one corner for my overflow and the last guy that owned my tank removed the quarter sized punch-outs next to the inlet slots and some of my livestock gets into my overflow then get stuck on my strainer and dies. Is their any device which stops up the semi-circles that have been removed? Thanks, Spence <I would cut or have cut a thin piece of acrylic sheet, with overflow slots... and adhere (carefully, with acrylic solvent... this in place on the face of your currently modified overflow. Bob Fenner> 

Gluing acrylic Hi, < Hi. > I am building an acrylic sump.  I have bonded the pieces together using a chemical that welds the acrylic.  I was planning to use 100% silicone at the joints to add extra strength and help guard against leaks, but from what I have seen here at WWM it is not recommended. < No, but I have built lots of acrylic items and I use a very thick (like honey) acrylic and make a bead all along each edge. > I found a product called Lexel which is supposed to be clearer and stronger than silicone.  Has anyone at WWM heard of this or have any experience with it? < No I haven't. But if you are using an acrylic weld like Weldon 4, try just going over each seam with something like Weldon 16. > Here is an online brochure for the product: http://www.sashcosealants.com/home_improvement/pdffiles/lexel_brochure.pdf Thanks, < May want to swing by a local plastic shop in your area to see what products they cover. > Dave <  Blundell  > Tank repair I've a problem with the plastic trim on the top of my 55 gallon fresh water aquarium.  I've looked at many questions you've listed but did not see mine, specifically. It was a saltwater tank that crashed, so I was cleaning it out thoroughly.  While turning it onto its side, I accidentally broke the cross member piece of plastic (part of the trip on the top of the tank.)  On my other 55 gallon tank, its the piece of plastic that divides the top of the tank in order to accommodate two separate lights. I put the tank back together, filled it with water and began the pumping process, etc.  There is a very large wooden light holder that fits on top (lighting for salt and a 75-watter).  When I put this top in place, I noticed that the lid would not close correctly.  I looked at the front of the tank and noticed a slight bow to the plastic strip on the front side and back side.  I'm assuming that if the strip is a bit bowed, so are the front and back sides. I noticed no leaks, but for safety and peace of mind, removed half the water and shut down the tank.  Here's my question:  given that the trim really doesn't support the tank, per se, can I fill it back up and use a clamp to pull the front and back sides toward each other?  Just enough to remove the bow and not crack the trim?  At first I used duct tape and it did the trick until the lights warmed the tape up and it began to expand.  The clamp won't be visible as the large light-holding top will disguise it.  Also, the clamp ends will attach only to the plastic trip, not the aquarium Plexiglas. <Owen, "aquarium Plexiglas".  I'm thinking this is an acrylic tank.  If so, just get a piece of acrylic, 1/4" thick, cut to the width of the tank by about two inches wide, then with acrylic cement, fasten the new cross member to the top of the tank.  James (Salty Dog)> Thanks for your help. Owen

Acrylic repair Salty Dog, Thanks for the reply and the suggestions;<You're welcome> I'll give it a shot.  Our pet shop here doesn't carry repair parts....would Lowe's or Home Depot carry acrylic? <Owen, Don't know. If they don't have it, try a glass repair shop. If they don't carry it they can probably lead you in the right direction.  Also, look in the Yellow Pages under acrylic.  Good luck.  James (Salty Dog)> Thanks Owen

Cleaning the Skimmer Collection Cup I notice that the interior side of the collection cup of my AquaMedic skimmer is getting "cloudy" although the weekly cleaning with a soft brush.  Do you know some product to use in order to remove this plastic cloudiness ? I have tried: bleach.. <This is the worst thing you can use on acrylic. It will discolor it.>  ... and vinegar without success. With "Benzine" I notice that the plastic became transparent / clean but only after a lot of applications in the same small portion of the cup.  Thanks in advance.  Best regards, Fl?io Ribeiro  <You could try an acrylic cleaner/scratch remover available from Drs. Foster & Smith and other mail order aquarium places. Good luck. James (Salty Dog)>

Picture of crazing I read your Q and A section about acrylic aquarium repair and my question was about crazing.  Mr. Fenner stated that one should take a picture and ask an expert to take a look at it so what do you guys think??? <This is... crazing for sure> should I scrap it or is there some way to repair this monster it's 240 gal standard this is the only real tank flaw it's about 3 or 4  years old. please tell me I can fix it      <I wouldn't scrap the tank... for fear of it rupturing... if this is all the apparent stress cracking there is. If it worries you, solventing a thin sheet/piece of acrylic over the area (with the tank empty) may render the crazing less conspicuous while adding strength. Bob Fenner>

Re: picture of crazing Thanks so much I really appreciate your advice I think I am going to melt a little acrylic on there you can't really see it when the hood's on. my concern was more structural.     Thanks again Mr.. Fenner <You're welcome my friend. Bob Fenner>

Tru-vu built-in overflow question I just got a used Tru-vu 100 gallon long (60x18x20) tank with 2 overflow on each corner. Question is internal overflow size is about 6x6 do you know how much gph is rated? I could not find this info from Tru-vu website... <What is the diameter of the through-puts? You might call them as well>   I was thinking about using 1140gph external pump on this tank but maybe this overflow draw more water than 600gph... <? What?> Also due to moving this tank (forgot to take off bulkhead during move) on both side near overflow area I have crack (not near by edge but near by internal overflow L shape area) which is about 2 inch (Both overflow area affected) <Bunk! Happens all the time.> I put 1/2" tick (5x2 and 3x2)acrylic outside of overflow L shape and inside overflow square shape acrylic (2x2) and glue them with tape plastic's glue do you think this will be enough?.... <Should be... I hope you're referring to having solvented pieces over the cracked areas and holes and re-drilling them> once I have about 100lbs liverock 100lbs live sand and water... I am getting worried... <I would fill and test it... outdoors> Maybe I should send you some pictures... Thanks Chris <Bob Fenner>

Bonding Silicone/Lexan Plexiglas Could you tell me if silicone will attach Lexan Plexiglas to a glass aquarium or if you can only attach glass to glass with silicone? Thanks, Amy <Silicone will weakly bond Acrylics, but are not to be trusted in aquarium applications of any real size/depth. Solvents for this purpose are the route to go. Bob Fenner> Repairing a hole in a sump When I recently tore down my tank I left a heater on in a small amount of water in the sump. It is acrylic, It burned a hole in the bottom and side with some bubbling of the acrylic.  I was wondering if I could cut out the affected area and glue some new plexi over the top of the cut out area.  It is a hidden sump so it doesn't matter what it looks like, just cost a lot so I would like to recover. Thanks, Mike <Actually, if the acrylic isn't too bubbled, you could just cut or have cut some small pieces of sheet (look in an acrylic outlets "bargain" box or ask for scraps, cut-offs...) and simply silicone them in place on the inside, over the holes, damaged area. Bob Fenner> How much bow in an acrylic tank is normal and safe? I've recently obtained a used 55 gallon acrylic tank and it really bows.  The tank dimensions are 48x13x20. When full of water the front bows out 5/8" and the back 1". <This IS quite a bit... for this thickness material, though acrylics do vary somewhat... and somewhat unsettling in that the bulge isn't about the same front and back... But, not totally out of order, and very likely nothing to worry about> I'm trying to determine if this is safe to put in the house or not. <Should be fine> Your thoughts or maybe where I can turn to get an answer... Todd M Howe <Bob Fenner> Help!! Tank blow out! Bob I have a tank that is 45 13/16 inches wide by 94 1/2 inches long by 33  7/8 inches tall One of the long sides blew out due someone putting their full  body weight on the top while retrieving a fish. It first just popped the seam by a couple of inches and this guy said he new how to  repair acrylic tanks. But as you can imagine he has disappeared. Now I have  no one who can repair my tank. Desperately seeking an acrylic tank repair person  in Downey, California. Sincerely,   JC Benavides <The tank can be repaired... should be drained, dried, and a square dowel inserted in the (I would do the whole inside edges) inside corners... take care to look carefully at and MARK the outside edges of the doweling that are curved (IMPORTANT: Note that only two of the four dowel edges are flush, the other two are concave...) and all solvented into place. Bob Fenner> Toxicity of Sea Clear acrylic scratch remover Is Sea Clear acrylic scratch remover toxic to fish-can it be safely used inside the aquarium to remove scratches? Thank you, Sue Kennedy  :) <Not very toxic... so okay to have bits fall into the water, but best to lower your water low enough and remove the residue after rubbing as much as possible. Bob Fenner>

Tru Vu (acrylic tank re) Repair Howdy, <Hi there> I am very glad I located your site and appreciate the valuable information you offer.  I am in the process of repairing a 55 GAL Tru Vu acrylic aquarium which has some minor leaks.   <Very unusual... I sold these tanks for several years... none were defective, or became so> I am concerned because I used the traditional method for a glass aquarium and the tank is acrylic.  Last night I applied DAP 100% Silicone Aquarium Sealant to the length of the interior joints. <Oops> Do you happen to know if Aquarium Sealant is going to work or if I need to get out a razor blade and start all over with the Weld-On product you mention in  your postings??? <You do need to cut out the silicone and use the solvent. Bob Fenner> Please advise. Sincerely, Dan May

Acrylic tank Hello, <Hi Audrey, MacL here with you today.> Sorry to bother you but I found you on a search and wanted to ask you a question. I just bought a used Acrylic 60 gallon tank. I was so stupid and cleaned it with a ......... and now my tank is very dull. <Acrylic tanks get scratched extremely easily and some chemicals "burn" them.  Its pretty easy to restore the shine though. I'm assuming the tank is still empty. I personally have had good luck with the Novus products. They have several types of polish.> What do I do??  <Find a plastics store in your local phone book and ask them if they carry the Novus polish products. I think you are going to need all three of them to bring back your tank.> Please help me. <Hope that helps. MacL> Thank you, Audrey

Acrylic Wall Thickness for Large Tank 7/17/04 I am building a very large tank in the shape of an equilateral triangle.  The dimensions are 24 feet long by 8 feet to the point of the triangle by 4 feet high (or deep).  It will be placed on a strong 18 inch concrete floor.  I am guessing that 2" for the sides and 1 inch for the top and bottom should hold well but I am just basing that on my limited engineering experience.  Do you know how I could find out if these dimensions will be OK.  Can you recommend any structural engineers if I need one or is it not that complicated if I know how to figure it out.  Thanks Dimitrios <Hi Dimitrios!  I hope when you say that you are building this tank, that you mean you are having it built.  This is not a DIY project!  I would begin by contacting some of the following:  A large public aquarium, Reynolds Polymer and San Diego Plastics.  I would consult a structural engineer about the floor.  A public aquarium should be able to direct you to large tank manufacturer (SD Plastics is one, but this project may be beyond even their capabilities).  Reynolds polymer makes very large, very thick acrylic material for public aquariums.  They can probably direct you to a manufacturer that deals in large display tanks.  There are wall thickness calculators on the 'net for acrylic tanks, but they only apply to rectangular tanks.  Good luck!  Adam>

Removing Scratches From Acrylic Aquariums I just recently purchased a brand new Sea Clear Acrylic aquarium and when I was fumbling around with my rocks in the aquarium I noticed that the acrylic was scratched rather easily.  It was very disappointing since this was a new tank. <I can relate! I love my acrylic tanks; swear by 'em for strength, but I hate the scratch aspect!> Scratches are rather light, I realize now that acrylic SCRATCHES very easily. <Yes, it does! Be careful, also, if you use a magnetic "algae scrubber", and have a fine bed of sand. These magnetic scrapers can pick up bits of sand on the pad and leave full-length scratches! I know, 'cause I've had it happen, myself!> My question is, is there any way to remove light scratches on acrylic or are they pretty much permanent?  Is there any method or product that I can use or a web site that you can refer me to that may help me out with removing these unsightly scratches?  Thank you very much for any information you can provide.  Love the site. <Well, there is an "acrylic scratch removal kit" by Rainbow Lifeguard (now Pentair Aquatics), that you can get online from Dr. Foster & Smith, among others, which consists of varying grades of fine grit sandpaper, used one after the other, getting progressively finer. It takes a lot of patience, and you must be very careful, but it does work. Hope this helps! Regards, Scott F>

Coralline Algae and Acrylic Aquariums 1/14/03 Hi Bob or Crewmate, <Hi Joseph. Adam here tonight.> I haven't even received my custom acrylic tank and I'm already fretting over scratches.  Bob, in his book The Conscientious Aquarist recommended acrylic tanks over glass.  I just started reading The Reef Aquarium and Delbeek and Sprung suggest that acrylic tanks are more suitable for fish only because cleaning the coralline algae off the walls will scratch the acrylic due to the calcium. <A question for the ages!  Some folks swear by acrylic, some swear at it!  Acrylic is a better insulator, is clearer, is lighter and is more shatter resistant, but scratching can be an issue.> Just how much of a problem are scratches with an acrylic tank?  If I am careful and use the proper tools to clean the tank, will I be able to enjoy watching a marine environment in my home for many years without seeing obvious scratches on the acrylic panes?  Even though I am willing to invest substantial time, energy and money in setting up and maintaining a reef aquarium, I am not willing to do this if, after a few years, I am seeing a scratched viewing panel first and a reef second.  I would just as soon fill the 145 gallon tank up with freshwater and goldfish.  Thank You,  Joseph Rouse <There are a few tips for keeping acrylic tanks scratch free.  First, clean it often to prevent heavy build up of coralline (a cleaning magnet is a great aid here).  Second, be very careful to use acrylic safe tools and don't trap any sand or grit in the tool.  Lastly, just be generally careful in how you work in the tank, place rock, etc.  There is no doubt you will get some scratches, but under water they are nearly invisible and shouldn't detract much from your viewing pleasure.  Best of luck!  Adam>

- Acrylic Scratches - Good morning, My question is as follows: I have an acrylic tank and while I was setting it up a few scratches appeared inside the tank and I would like to know how I could polish it, I have read about a tool called router, but I have no idea if it is the tool I need or if I could introduce it inside the water. <A router is not your friend in this endeavor and in fact the only power tool practical for such things is your own arm-power. There are a number of scratch-removal kits which involve fine grade abrasives... some can be used wet, others must be used dry. Both types are available at most online retailers. You find however that it takes longer than is practical with less than satisfactory results... you might just want to get used to the scratches.> Thank you very much.  Jorge <Cheers, J -- >

Can Some Fish Scratch Acrylic? Bob, <Yes> I have read at one website that some fish will "mouth" the sides of an acrylic tank and make scratches.  The fish listed included angels, butterflies and triggers.  Is this something for an acrylic aquarium owner to be concerned about? Joseph Rouse <Mainly just some of the tetraodontiform fishes (triggers, large puffers)... but compared to other sources of scratching (mainly aquarists with cleaning tools, trapped bits of gravel...) no biggee. In the world of possibilities, this is minor spuds. Bob Fenner>

-Removing scratches from acrylic tank- Hello, I found your site while trying to figure out what to do with my 60 gal tank.. My wife was trying to be helpful and scrubbed the inside of my acrylic tank with one of those sponges that have the green scotch pads.. <Ouch!> Needless to say, the front of the tank now has a "clouded" look to it.. We have since moved from So Cal, to Grants Pass, Oregon.. While the tank is now drained I'd like to get the scratches "polished" out.. I have read of the product called "Novus" on your site.. Is this something I can do myself? <Absolutely, and I hear it works wonders.> Or is it something I have to have a supplier apply? Is there any supplier in the Grants Pass, Oregon area that I can purchase this from? <No idea, but I did find an e-tailer that carries it http://www.tropicalfishstore.com/careproducts.htm> Any help will be much appreciated! <Good luck! -Kevin> Thank you, George King

Removing Scratches on tank Hi, <Hello there> I love your web site (Bob along with the WetWebMedia crew, along with your book.  It has helped me so much in my years of reef keeping. <Ah, good. Our intention> I am, however, puzzled by one question.  Whether or not I can actually use the Novus product underwater?   <Mmm, no... you must drain the tank down to below this point... though some water may remain in the tank... and the livestock too if there is enough space for them> In one post you claim it can not be used, and in another you claim it can.  I have cited each for you below.  I know that toothpaste method works for certain to remove light scuffs inside the tank, I have done this several times without any ill effect.  I just wonder how safe Novus 3 or Novus 2 would be underwater, in a fully stocked reef with corals, fish and inverts.  I would hate to blow thousands or dollars just to remove a scratch.  So, which do you recommend, using Novus underwater, or not using it underwater.  Thank you in advance for clearing this up. Jon <Sorry for the confusion. The second piece is not clear, but it is my intention to convey that the product itself is NOT toxic if it gets into the system/water to some extent (have done this myself), but does need to be worked, rubbed-in in the air... that is, with the tank drained down or emptied. No problem with some of the resulting "dust" getting into the water though. Bob Fenner> Taking out scratches from the inside Bob, Do you know of any acrylic scratch removal kit that works underwater? <No... all require draining the system at least down to the level of the work. Bob Fenner> Thanks, Lee Re: follow-up on removing scratches in acrylic tank using Novus, and visit to Phoenix Thanks, Bob, for your very prompt response! It is comforting to know that your experience shows Novus 1, 2, and 3 can be used on the inside of an acrylic tank without harm to the fish. I bought the Novus 1, 2, and 3 yesterday afternoon. <Wish I had made these products!> As a follow-up to my earlier email to you, can I leave my large jardinei in the tank while I am working on removing scratches with Novus 2, and if necessary, Novus 3. That is, from a chemically (nontoxic) safe standpoint?   <As far as I'm aware, yes. Have used these in "full tanks", fresh and marine, with impunity> There will be about 4 inches of water for him to stay wet; <And not jumping out!> the lowest scratch to be removed is an inch above this water line. Thanks in advance for your advice! BTW, Phoenix has a dry heat this time of year ... and its been mild this week. Its the August monsoon that you want to avoid. Steve <Will be out there this Thursday with some friends/associates, giving a pitch at the DMS (Desert Marine Aquarium Society). Stop by if you'd like. Bob Fenner>

Acrylic tank leak Hello.  I recently purchased a used 125 acrylic tank and it has a leak.   There is a crack on the bottom right near the front of the tank.  It does go all the way through the tank and that is where the leak is.  I was wondering if I could glue another piece of acrylic or Plexiglas along the bottom of the tank (inside) all along the front edge.  If that will work, what would you use to glue it?  Should I use crazy glue and activator on the crack first?  Please help!!! <You can solvent (not really a glue... as there is nothing left between the melded materials) a piece of acrylic here (look for "square doweling" at an acrylic outlet (it's only truly flush on two of the four sides, and you want to fit these two against the existing panels). Look for Weld-on products for solvent. Bob Fenner> Thank you, Ron

- Scratches in the Acrylic - I have an acrylic TruVu aquarium and it is scratched on the outside and looks hazy in some parts.  What can I do or use to take these scratches out? Yoquin <There are several commercial 'acrylic scratch-repair' kits out there. Look on the online retailers and you will find them. Cheers, J -- >

Tough acrylic cleaning question I have purchased an acrylic tank from a friend. He had applied some clear shipping tape to the openings in the lid. I have tried elbow grease and my credit card but the stuff just isn't coming off very well. I've looked around on your site and didn't find anything appropriate to my situation. I know not to use Windex or anything else ammonia based. I've thought about goof off but that's petroleum based. Do you have any ideas. Thanks <I would try "citrus based cleaners" here first. Do with the tank empty and make sure and wash any residue from the surface. Bob Fenner>

Re: tuff acrylic cleaning question, repair Thanks Bob, I ended up having to use lighter fluid to clean this stuff off, it was caked on pretty good. <As long as you're "right there" wiping off the excess (so it doesn't melt the acrylic) this works pretty well> I have another question. I found two small chips on the corner of the bottom plate, about 1/4" around and maybe 1/8" deep. The acrylic is 1 inch think at that location so I don't think it will be harmful. Do you think that I can put some acrylic glue in the chip just to give it some strength in that area. <Might help. Have you considered adding some "square doweling" in the corner. This stuff comes in stock sizes with two of the four sides "square" and the other two a bit concave. You solvent (as in with Weld-on) the two flat sides to the tank inside corners. Bob Fenner> Thanks

Scratch removal and polish on inside of tank using Novus products Great site for info! I have a Tenecor 180 gallon acrylic tank that has numerous fine to moderate scratches in the upper half of the tank as a result of five large red hooks bouncing off the front panel when it tries to compete for food against a 20 inch jardinei. <Neat> I am removing the red hooks and want to remove the unsightly scratches inside the tank.  Tenecor sells a group of products called Novus #1, 2, and 3 that is supposed to remove these scratches, as well as a micro mesh kit that does the same. <I have used these products. They work... but the micro mesh reminds me of the Karate Kid series of movies... rub on, rub on... and takes about as long to remove the finer scratches it makes as re-watching the whole series!> In doing the scratch removal, I would prefer to use the Novus products  The micro mesh kit seems very tedious and I do not feel comfortable with the acrylic particles being sanded off and mixed in with the water and substrate. <Me neither> But is it safe (non-toxic) to use Novus on the inside of the tank after the water is taken out of the tank to the level of the lowest scratch; or am I stuck using the micro mesh sandpaper? <I'd try the two grits of the Novus first>   If I can use the Novus product inside the tank, is there additional prep needed after the scratches are removed and the front panel is polished, before I can refill the tank? <No further prep... just wipe up the bits of "scum" with a damp paper towel> Thanks for the help! Steve <Thank you for writing, good luck. Bob Fenner>

Re: follow-up on removing scratches in acrylic tank using Novus, and visit to Phoenix Thanks, Bob, for your very prompt response! It is comforting to know that your experience shows Novus 1, 2, and 3 can be used on the inside of an acrylic tank without harm to the fish. I bought the Novus 1, 2, and 3 yesterday afternoon. <Wish I had made these products!> As a follow-up to my earlier email to you, can I leave my large jardinei in the tank while I am working on removing scratches with Novus 2, and if necessary, Novus 3. That is, from a chemically (nontoxic) safe standpoint?   <As far as I'm aware, yes. Have used these in "full tanks", fresh and marine, with impunity> There will be about 4 inches of water for him to stay wet; <And not jumping out!> the lowest scratch to be removed is an inch above this water line. Thanks in advance for your advice! BTW, Phoenix has a dry heat this time of year ... and its been mild this week. Its the August monsoon that you want to avoid. Steve <Will be out there this Thursday with some friends/associates, giving a pitch at the DMS (Desert Marine Aquarium Society). Stop by if you'd like. Bob Fenner>

Acrylic Tank Scratches Hello all: <Hi there> Just a real quick question so I don't botch things up. We have a 125G acrylic that has developed some scratches on the front panel. I must have failed to notice a tiny bit of gravel in the pad while cleaning, as I am vigilant about making sure that no debris is in the pad before I use it on the panes. <Good idea> Nonetheless, I went on the website and found Bob's response to a similar query, where he recommended using a gritty toothpaste to remove minor scratches. I was wondering if this procedure can be done while the scratches are under water. I can apply the toothpaste without any difficulty, as the scratches are within arm's reach. However,  I am very concerned about the effects, if any, that the dissolved toothpaste may have on my fish. Thanks for the clarification. Mitch <Mmm, they may end up with "whiter, brighter teeth" and a "significant reduction in dental caries", but should otherwise be fine. Bob Fenner>

Re: Acrylic Tank Scratches Thanks, Bob...I am sure that my porcupine puffer, with his sizeable bite, will appreciate the brushing! I will try and get a paste that is recommended "by 4 out of 5 members of the American (Fish) Dental Association." Mitch <Ha haha, heehee! Be chatting. Bob F>

Acrylic Scratches A few months back you mentioned a way to remove scratches from acrylic aquariums even under water.  Due to travel requirements I was out of town for the next few days and missed it if you elaborated on the subject.  I have checked the web site I was directed to by Bob but still haven't found any specific instructions.  Can you please help me out?  Thanks <Alright, I hope you can find this one! Most scratches can be polished out, depending on depth....  There are kits available from most on-line suppliers carrying acrylic tanks that use abrasives in finer and finer grades to remove the scratches and restore a lustrous finish, even under water with some. You might start by searching for these products at some of our sponsors!  Thanks for your patience.....Craig>

Invertebrates that scratch acrylic tanks 5/11/03 Hi can anyone tell me which invertebrates can scratch my new acrylic tank?   And which ones won't do any damage to the tank? Thanks, Ron <mostly limited to mollusks with a radula (hard rasping tongue-like aspect- Gastropods predominate.)... and some echinoderms. Generally not a big deal. Best regards, Anthony

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-? I have built a corner tank with bent corners( had a fab company bend) which cost a pretty penny. I tested it out and there was a very small leak so I went back and applied more solvent and tested again, no leaks. I have had water in it for about 3 weeks just to see if there would be leaks after a period of time and there were none. In some of the seams though there is some air bubbles I have tried to fill them in with solvent but it does not seep into the bubbles leading me to believe that the edges are sealed. Do you think that these bubbles could present problems in the future or what do you think? <Likely not a problem if it hasn't been so to date. Bob Fenner> Thanks for the info,                      James Wesley

Acrylic tank cracks? (crazing) >Hi all at WetWebMedia, >>The crew says hello, Marina at your service. >First I must confess your website has been a great help to me for the past year in looking up what to do when in doubt with my current trigger FOWLR set up. >>What a confession.  Now, what penance...10 lashings with a wet noodle, then eat the noodle. >Now, on to the point... >>Oh yes, there was a point.  Having too much fun, back to work! >I have recently purchased a used acrylic tank 76 1/2 x 15 x 30 (made by a local company).  The tank has an overflow to the left side and that is why it is longer than 72 inches. Total volume is 150 gallons. Now, the previous owner had attached a piece of plywood or strip of wood across the upper edge of the tank to support a DIY canopy. While I was cleaning the tank I removed the wooden strip which was attached with adhesive tape. Immediately I noticed a series of parallel marks that looked like cracks on the outside of the tank. There are 3 clusters of less than an inch marks/cracks on the upper side (roughly half an inch before the brace starts). I'm not sure whether I caused that my pulling the wooden piece , or whether it was there from before and the previous owner had attempted to conceal it. >>Bingo, I think it was there and he wanted to conceal it. >Also, the same marks appear on the back side of the tank along the upper side but they are not as long. This leads me to believe that I did not cause the damage (if it is to be perceived as damage).  Do you think if filled with water, it will cause a leak down the road? >>Very well could be a problem.  I have a recipe for filling such "tight" cracks (please, please, let's keep it clean here), but have never used it on a tank that is so peppered with these cracks. >Should I make arrangements to have it repaired, or sell the tank? This will be a FOWLR tank with 1 niger, black patch, blue line triggers. Currently, all are at 3-4 inches long.  I would greatly appreciate an opinion on this...keep up the good work on WetWebMedia. >>Well, if there is someone who can make good repairs and they can price them out for you, allowing that the repairs are not going to end up costing you the price of a new tank then I don't see why not go that route.  I would first fill the tank in my yard, on a flat area, to determine several things.  First: is it going to leak?  Second: are the cracks just so unsightly that I don't want this as a display tank.  Third: are the repairs proposed (my recipe will only stop leaks, you'll still be able to see the cracks quite well) cost effective.  At this point, only you can determine these things, then go on from there. >>My recipe for repairing these cracks is that you must first ensure that they are completely free of any and all debris, including any mineral/salt deposits.  Once the cracks are to a pristine state, you need on hand liquid cyanoacrylate (Superglue) and the catalyst used for acrylic nails, and a small metal stick (like the tool used to push back cuticles...hey, I'm a lady!).  What you want to achieve is to get the Superglue to seep into and fill the cracks completely, then IMMEDIATELY place a drop or three of the catalyst onto it.  These substances react with each other (the hotter and drier the weather, the more immediate and extreme the reaction) to fuse with the each other and the acrylic to form a tight bond.  However, as I said, you will still be able to see the cracks--this is a method I've used on non-display tanks only. >>Good luck!  Marina Location of marks _____________________________________________________ | """" """ "" | Hope this helps to visualize | | what I wrote above. | | | | | | | | | | _______________________________________________________   <-- front panel. Front panel 1/2 inch thick. Bottom panel is 1 inch thick.

Acrylic tank cracks? >Thanks for replying Marina, >>My pleasure, Dimitris. Well, I called the LFS that sold the tank to the person that I bought it from and the local guru there said that if those clusters of lines are not close to the seams or corners, I shouldn't worry about it. He said I might want to buff it with a 3500 rpm electric drill, but he thinks due to the thickness of the front acrylic panel( 1/2 inch) that it should be ok. Personally, I could not see any of those surface lines |||| |||| |||| extend past the surface. They had no depth, just like those spider web like ones on the back panel. I guess I will fill the tank up with water to see if it will leak. >>By your description, it sounds as though the only problems you'll have will be cosmetic.  C'est la vies!  Marina

Enlarging the access holes on the top of an acrylic tank Greetings! I started out with a 29 gallon reef, got a 65 when I found out the hard and soft corals don't get along, then got another 29 to keep the anemones and clownfish in, and my "quarantine" tank is now holding the huge evil red hermit crab I inherited that will eat anything ...this reef addiction gets out of hand quick, doesn't it?!! I no longer have the incompatible soft corals, want a bigger tank for more hard corals and flasher wrasses (the little sh**s can jump through the holes in eggcrate, will use an even tinier mesh screen), and need to get things consolidated for tank stability. I have only one non-knowledgeable fish-sitter available if I have to go anywhere, and the little tanks are too prone to fast crashes if the power goes out and the GFCI trips when everything tries to come on at once, or to temperature or salinity fluctuations, or if anything dies.... Still no reef in the backyard (whaaa!), but came up with the next best thing (at least my checkbook thought so)--I got a great deal on a used complete saltwater setup, including a 180 gallon (Clear-vu?) acrylic tank (would have preferred glass for ease of cleaning, but oh well) 6' x 2' x 2' made of 5/8" acrylic. There are two top access holes on it, but I'm short and they are so small and far in that I can hardly get my arms and hands in towards the bottom of the tank. When it's set up with a deep sandbed this will help reduce the depth, but even so, if I can't reach all the tank sides I'm rapidly going to have only scraped view holes of my reef through the pink coralline algae! and even worse--if I can't reach in to all parts of the tank I may have to disassemble the rockwork every time I need to get a dislodged coral frag or (please no) something that died out of the rockwork that I can't reach with tongs--not a pleasant thought. I was considering cutting the holes in the top larger, so that they were at most 3" to 3.5" away from the edge of the tank (on front and sides--along the back are narrow openings for external filters that are already on the edge, so I don't know if I can go in any further), instead of the 6+ inches they are now. How close to the edge can I go without compromising the structural support of the top? (do you need a drawing or detailed measurements?) How wide does the middle bar need to be? (currently about 16") or ideally, is there some way to build a reinforcing braced edge along the top so that I can cut out most/all of the top? out of what materials? Would I be better off building a glass tank like I was going to do in the first place? (between the chiller, MH lights, two big Iwaki pumps, 500 lbs of "live" (more like base) rock, and a full 50 gallon setup "thrown in" I'll get my money's worth even if I do have to scrap the tank) Thanks for your time! My corals and fishes are looking greedily at the Big Tank, and at me as if to say "well, why aren't we in it yet?"       --Kari Yanskey (and if Anthony is answering this, at least this time it's NOT the "Preamble to the Constitution", but you'll probably dub me the "queen of parenthesis" or something. Keeheeheeheehee!) < I wouldn't mess with it here, you will likely just end up with bigger problems.  Also since you are using metal halides you will want as much support as you can get because of the heat.  You should be able to reach most of the algae you need to get at with a long handled scraper such as the one made by Kent. Best regards, Cody.>

Re: want to cut out top of acrylic tank part 2 Ohh, sick sinking feeling--did I say the acrylic was 5/8" thick? in the message I just sent you?  it's 3/8" thick--makes a real difference.... thanks!           --Kari <That's better! Cody>

Acrylic Nightmare Hi, <Hi there! Scott F. with you> This is in response to a prior FAQ.  I have an empty 55 gallon acrylic tank that's in need of some serious scratch removal.  I wanted to know if the headaches in trying to do this myself is worth it.  I've seen a few of the various kits that are available, but I want to know if there's any one particular kit that is recommended over another.  If it's feasible, I'd like to get the tank professional restored but I don't have any clue where to take it.  I live in the Orange County/Los Angeles area.  Please help! Thanks so much.--Chris Sartor <Well, Chris- "worth it" or not is a relative term, I guess. Depending on the severity of the scratches, it may be almost impossible to get 'em all without days on end of work. I won't kid ya- it's a very tedious process, and if you're doing a lot of scratches, it can become a "lost cause" at some point. However, if you have the time, and don't mind the effort- you can certainly pick up a tank at a good price and get it quite a bit nicer than it is now. As far as having it professionally restored- this may be one of those things that make it not worth the $$$. If you can find someone who can do it, they may charge enough to make purchasing a new tank look attractive! I'd try contacting a manufacturer or two for possible referrals. In the LA area, I think you could call Advance Aqua Tanks (Clear For Life), and see if they have some ideas. Good luck! Regards, Scott F>

Scratching His Head Over A Scratched Tank! Aloha WWM Crew, <Howzit? Scott F. with you today> Thanks for all your help.  The service you provide is second to none (no ka oi). <Thanks for the props! Glad to hear that we've been helpful for you!> I have written a few times about my 55gallon FOWLR. I'm thinking about purchasing a used 200 gallon acrylic tank, but I have some questions before I  jump into such a big investment.  First, the tank has many huge scratches on the inside as well as the outside of the tank.  The current owner has many kids that destroyed the outside of the tank. <Those darned kids... :)> There are so many scratches that you can barely see into the tank.  The tank is a SeaClear and seems to be in good condition minus the scratches. <An all too common problem with used acrylic tanks! But also a common reason why used acrylic tanks can sometimes be had for cheap prices!> I was wondering if the tank would be worth the headaches of trying to remove all the scratches.  Are there any other issues I need to be aware of?  Could the scratches lead to a leak or cause the tank to crack?   <Well, Jeff- if they are basically surface scratches, they can actually be removed with a special sandpaper kit made especially for this purpose. It is a rather tedious process, unfortunately...but it does work! As long as the scratches are not "deep", or near the seams, then the tank is probably structurally sound...Do check on the condition of the chemical "welds" on the corners of the tank, to make sure there are no signs of them pulling away from each other. As long as the tank is structurally sounds, and as long as you're up to the challenge of sanding away the scratches (and if the price is damn good!), you may be able to score a killer deal on a tank that you can get lots of usage out of. Do check our sponsors for these acrylic refurbishing kits. There are other places on the net that offer these special grades of sandpaper. It's worth a shot.> Mahalo Nui Loa-Thank you very much, Jeff <Malama Pono and Ahu'i Hou! Regards, Scott F>

100 gallon acrylic tank bowing Hi there, <HI> I have what may be a silly question for you guys.  We just upgraded from a 30 gallon glass tank to a 100 gallon acrylic tank.  We've got all the equipment setup and working, the tank is full, and we have noticed that the front and back seems to be "bulging" out about an inch or so.  We figure this is probably normal due to the weight and flexibility of Plexiglas, but are somewhat paranoid - that is a lot of water in there! <It sure is a lot of water, and I would not want it on my floor. Acrylic tanks will bow a little bit, but an inch sounds dangerous to me.  I would drain the tank and install a brace, possibly a padded bar clamp.  We have some FAQs on acrylic tank repair you might want to check out. http://www.wetwebmedia.com/acrylicaqrepair.htm http://www.wetwebmedia.com/acrylictkrepfaqs.htm > Can you tell me if this bulging is normal or if we should be worried about the impending flood? <I'd worry, I tripped over a 5gal bucket dumping water all over my floor, and that was a pain to clean up, I would not want to imagine 100gal. -Gage> Kristin, BC, Canada  

PLEASE HELP!!!! <Acrylic tank coming apart> I am panicking big time!  I wanted to check with you to see if you had any ideas or suggestions.  I have a 160 gallon acrylic tank.  I got it about 6 months ago on EBAY and it has been absolutely wonderful.  It looked very well made with the top being completely molded into the frame with just two cut outs as openings.  It is not leaking at the moment but yesterday I saw something very disturbing happening.  It looks like there is an extremely very slight separation in the seam of the side wall coming into the back wall.  The separation is on the outside and air is getting into the seam.  I feel no separation at all on the inside.  No leaking water yet so it has not made it through the 1/2 acrylic to the inside I'm assuming.  It started at the very top and is moving down quite rapidly. . . it moved about 1/2 inch during the night.  I'd say from yesterday morning to this morning it is about 4 1/2 to 5 inches long.  You can see it clearly looking in from the front of the tank because the air is reflecting light.  Like I said so far no water leakage at all.  We put clamps on it this morning because I just had nightmarish visions of the entire house being flooded when I went home from work.  Were clamps the right thing to do?  Have you ever seen this happen before? <Have seen this happen before... the "whiting out" or crazing area is very bad news. DO IMMEDIATELY DRAIN the tank down at least half way. It may well separate at this seam!> Am I freaking out for good reason or overreacting? <I think you should (I would) freak out, and you're not overreacting.>   I'm guessing that I will need to get a new tank right away. . . so, I've looked into it and it will take approximately 2 -3 weeks for the store here to get what I need in.  I'm just hoping that the clamps will hold!!!!! <I would not count on this w/o lowering the water. Who is the manufacturer of this tank? Do contact them ASAP. They may well be able to expedite a replacement to you> As far as what tank to get. . . I loved acrylic for the reason that it seems so much more durable than glass. . . but since this has happened I don't know.  Would a 160 gallon glass tank be too dangerous -- should I keep going with acrylic? <Both are "reasonable" (safer than driving on the road) technologies>   One other reason I found that I don't like acrylic is that it is so difficult to clean without scratching.  I hate that but have put up with it because of the durability.    <Yes> Can you offer some much needed advice? If I did go with an all glass tank what brands do you recommend?  Is All-Glass on your list? <Yes... as well as Perfecto, Oceanic... in the old days Atlas, Odell> Also, please tell me if you would go with acrylic again for the durability. <We mainly fabricated and installed acrylic in Southern California... due to earthquakes... their greater strength during "shaking". Bob Fenner> Thanks so much!  :)

Acrylic Tank coming apart I've checked into it and I will have to wait 3 - 4 weeks for a replacement tank.  I'm am so stressed at the moment I don't know what to do.  If I drain the tank to below the crack I can't run the pumps.  How long can my fish safely live without a filtration?  P.S.  I also have live rock.  What to do????  HELP!!!! <Think on ways to add a sump (even a plastic tote) where you can place some of your live rock, run the water back and forth. But do drain the tank down> Thanks for any advice you can offer! :) <Will your local fish store your livestock for you while you await the replacement tank? Do ask. Please see here re moving, storing your gear, livestock: http://www.wetwebmedia.com/movingaq.htm Bob Fenner>

Acrylic Tank coming apart RE: PLEASE HELP!!!! (quick suggestion from Ananda) <Ananda here, hoping to lend moral support...> I've checked into it and I will have to wait 3 - 4 weeks for a replacement tank.  I'm am so stressed at the moment I don't know what to do.  If I drain the tank to below the crack I can't run the pumps.  How long can my fish safely live without a filtration?  P.S.  I also have live rock.  What to do????  HELP!!!! Thanks for any advice you can offer! :) <I'm going to let Bob answer, too, but I thought I'd pitch in with a suggestion. You could use 55 gallon Rubbermaid Brutes (the grey, white, and yellow ones are food safe) to hold some of your rock and water (and maybe even some of the fish -- don't know which species you have) until you get a new tank. Hang in there! --Ananda>

Cracked acrylic tank Do you see anyway of repairing this type of thing?  Could I drain the tank down and try some sort of glue?  Is there anything I could try before giving this thing up completely?   <Sorry to hear of this major problem. I would contact an acrylic manufacturer about repairing this tank although I hold little hope for repair. You would be safer just getting a new tank. At the very least I would empty this tank ASAP and follow the suggestions from the last email. You don't want to put this off until the whole tank spills on the floor> Thanks for your patience with me.  :) <No problem...That's what we're here for! David Dowless>

Re: PLEASE HELP!!!! <Acrylic tank separation) Hello again. . . was hoping you could give me some more pointers.  Here's what I've done so far.  I've drained the 160 gl tank down to well below the crazing (however it still keeps creeping!) <Keep draining till it stops> and have transferred the fish to a 75 gallon and have hooked up all of my equipment (wet/dry, skimmer, sterilizer, etc.) to this new 75 gallon.  I transferred some of their substrate and rocks too.  They seem to be doing fine however I'm worried that they will think they are being punished for going to such a small tank!!!  Will this stress them out? <Not as much as living w/o water> I've adjusted the flow rate (a Mag 9 is running the wet/dry) and have turned it down about a 1/4 of the rate it was going.  Is that enough or is the flow rate too high for the 75 gallon? <Should be fine> Here's my dilemma.  My VHO's and small power compact are hooked to the 160 gallon so I left a little water in there for the live rock and a pump circulating the water so that they could receive the benefit of the lights because the 75 gallon does not have any at the moment.    <Good plan> Will the live rock survive with just the circulating water and lights for 4 weeks. <Also should be fine> I couldn't add the Kalkwasser and calcium because there is no filtration, right?  Or, would it be better to somehow rig up a little power compact to the 75gallon and transfer the live rock in there with the fish? <You can measure calcium, pH and add supplements as you see fit> Will my excess water (that I really want to save since I spent months getting it perfecto!) that is being housed in large plastic containers and some in the old tank be ok for 4 weeks with just a circulating pump? Will it still be perfect with no fish being in it for 4 weeks? <Yes> The new tank will most likely take the full 4 weeks.  I've ordered another acrylic (has a lifetime warranty) from a reputable company (been in business 20 years) and have ordered the following dimensions:  72L x 18w x 34h -- is this ok as long as the acrylic is 1/2 inch? <... 34 inches tall? I hope your arms are long... I would have preferred either thicker material (mainly to reduce the degree of bowing and improve looks, looking through...) or to have made the tank wider, but shorter... to work on, support life> Would it be better to go with 3/4 inch?  The 160 that cracked was 1/2 inch and was 72 x 18 x 28 so I'm just going 6 inches higher. <Yes to the 3/4 (call and change if possible... NOW), six inches higher is a huge difference> Sorry to be so long winded but I have lots of questions -- hope you are full of patience today!  :) <No worries>   Trying to figure out why the crack happened in the 160.  What could have caused this? <Almost assuredly construction defect... the folks who cut and assembled the tank didn't make joints square, clean, did solventing in a high humidity (very common), or used defective solvent...> The tank was perfectly (I mean perfectly) level and I use VHO lighting (4 ft. bulbs centered across the 6ft tank) as well as one small power compact in the center.  I know MHs aren't smart to use with acrylic but I always thought VHOs were fine. . .am I wrong?  The crazing happened in the right back corner where the VHOs are really over it????  Any ideas of what happened? <Not much chance it was the lights, or anything you did... as stated, it is/was the manufacturer> Last question I promise!!  I was thinking of adding an angel fish before all this happened.  Would it be better to let my fish get acclimated to their new tank when it arrives and add the angel a few weeks after or should I add the new angel at the time they go to their new tank so everyone is claiming new territory? (I'm thinking the Angel will need to go in a few weeks after the fish have acclimated so it won't get the "I'm the king of the tank" attitude and might be a bit humbled?? <I think you'll be okay to add the angel... if it's "ready to go" (certifiably clean of parasitic disease)> Thanks for listening to me babble. . . I appreciate you more than you know!!  Would welcome any advice you care to give.  Thanks again! <Bob Fenner>

Tank coming apart follow-up Hello again. . . just a little update on the situation. . . all fish are doing fine and are acclimating nicely to their smaller 75 gallon.  All of us are anxiously awaiting the arrival (still have three more weeks to anxiously await) of the new tank so our lives and living room can get back to normal.  By the way, THANK YOU for all of your help during my crisis.  I literally don't know what I would do without you!!!!!  (PLEASE, don't ever get out of this business/hobby!!!!)  :) <Not likely, thank you> A quick question. . . I've, of course, been keeping my left over water that wouldn't fit into the 75 gallon in large Brute trash cans in the living room with the base rock in there and pumps circulating the water. One trash can sat for about a day without circulation -- is that water ruined? <No, should be fine to use.> Secondly . . . . I've transferred all of the sand (not live sand) into buckets.  They have a little water sitting on top but are not being kept in the huge trash cans being circulated.  Is this ok?    <Yes> Last question. . . I had been using a MAG 9.5 to run my 160 gallon.  I've been using it as an external pump (it seems to be working great) but recently read in a MarineDepot.com catalog that MAG pumps are not to be used externally.  Is this your opinion too?  What would happen if I continue to use it externally? <It may overheat, quit on you, but there are others who have used this size, line pump externally with impunity> But, this may be a moot point when you hear my next question.  Since I am going 6 inches higher and 30 gallons more with my new tank coming in will a MAG 9.5 be sufficient to run this fish/live rock only tank? What if I wanted to start slowly getting into corals (have VHO/PowerCompact lighting)?  Would I need a larger pump now for the extra height and gallons (if so, please recommend some) or only if I were to go with more of a reef system?  Thanks for your advice! <It may be time to upgrade then> I think that's it for now.  Again, A HUGE THANK YOU!!!  You are truly a lifesaver!!  By the way, do you ever come to Tallahassee and lecture at Florida State University?    <Have not yet. Bob Fenner>
Elizabeth

Acrylic tank cutting I would like to cut part of the top of my tank out and was wondering if you thought this was safe.  I emailed to ask Clarity Plus, since they made the tank but did not get a reply.  I would like to just cut where the red line is.  Its a 125Gal, so what you see there is replicated on the other side, I only want to cut this one side though.  Due to the extreme bow and flex in this small piece, I think it will be ok...I just wanted a 2nd opinion.  Going to post on the forum too though not sure how to host the picture for that. <Mmm, well, I would like to see there be a much wider (a few inches) long piece of acrylic be along the back edge where the original cut-out is... to strengthen the sides from bowing. But the present cut-out is what, where it is... It should be okay to make the cuts as you show them... but if you can, do consider "running a strip" of acrylic (like two-three inches wide, the length of the back of the tank) and annealing this to the top (with solvent) to brace the tank from bowing. Bob Fenner> Mark

Acrylic Scratches Bob- <Scott F. here this afternoon> I recently purchased a 65 Gallon acrylic tank. Not thinking I scrubbed the inside of the tank with a Scotch pad (green, abrasive cleaning pad). <Made that mistake before, myself!> I then installed my power compact lighting and turned it on and to my dismay I saw that I have tiny surface scratches all over the inside of the tank. Is there anything I can do to remove them? PLEASE HELP ME! Thanks, Mike <Well Mike- this has happened to just about everyone who's ever had an acrylic tank- so don't beat yourself up over it. There are "repair kits" available to remove surface scratches, but they do involve sanding with various grades of specialized sandpaper. The scratches can be removed, but the work is kind of tedious! Do consult the dealer where you purchased the aquarium for a source of these kits, then get to it! Good luck!>

Need help please (scratch, opacity from acrylic tank repair) hi bob I bought a 60 TruVu tank and had a scratch in it my LFS gave me some srk-1 to remove it now I have a big smudge is there some thing you can suggest I can buy to polish that out thx for any info <There are "finer" polishes (often scratch-removal kits come with more than one grade) to "polish around" such hazy areas... in a pinch, if the area is small, you can even use a gritty oral dentifrice (aka toothpaste) and a soft rag to buff out such blemishes. Bob Fenner>

Jim Dorsey, California Aquatics Bob, Oddly enough, Donna from Dr. Kaplan's office [Pediatric Urological Associates] called and, as you remember, you installed a Tru-Vu 75 Hex Tank in -oh about 1982. <Yikes! Yes, a very nice fellow, and great office staff as I recall.> Well, one of the kids knocked off the canopy [again] and we are having trouble finding Aquaplex. Did Bill Montgomery finally get how of the business? <I don't think so... but... pls see below> How can we do that? <Finally get out of the business? Wish I knew!> Do you know of any other acrylic canopy manufactures? <Yes. Have San Diego Plastics fabricate a sturdier replacement> Thought you might get a kick out of this one! Check out are site @ www.californiaaquatics.com Jim <Very nice. Be chatting, Bob Fenner>

Plexi glass glue Hi there once again, I have a question about the type of glue people use to put together plexi glass.  <Most folks use a commercial acrylic solvent... like Weld-On> I hear that the best way to glue two pieces together is to use a solvent called Methylene Chloride.  <This is a principal ingredient. Toxic, flammable, not generally available to the public.> can't seem to find it in Home Depot or Lowe's. Do you know where it might be available?  <Check with the businesses listed in your phone directories who sell or do plastic fabrication> I also wanted to ask if you know whether this solvent (Methylene Chloride) can be used to glue plexi glass+regular glass together, or is it just for plexi glass+plexi glass? <Only the latter> On another note, I'd like to thank you for responding so quickly, and for being real informative. It's advise like this, that I wish I had for everything I come across. Your help is greatly appreciated. Thanks, Hamilton, Riverside, CA <Glad to be here helping. Bob Fenner>

Re: plexi glass glue Thanks for your help, but I'm not quite sure about what you meant by (only the latter).  <The last statement... these solvents are only for acrylic to acrylic bonding> Can you describe this in another way? And is (Weld On) safe for fishes. Well I guess it is since you said everybody else uses it. Thanks for your help. <Safe after cures (a day or so)... it actually "leaves"... melting/melding the Plexi as one piece. Bob Fenner>

Acrylic Do you know of any way to buff scratches out of an acrylic tank? Thanks! :) <Yes... have spent a bunch of time trying to do so... slight liquefied abrasives, to papers to "heat burnishing". Please use the Google search tool on our sites homepage or indices (on WetWebMedia.com) with the terms "acrylic repair" or "scratch removal". Bob Fenner> Elizabeth K. Birdwell

Cracked Tank Hi there Bob I just cracked the bottom of my 180 gallon acrylic tank. Its okay it was empty. The crack maybe about 10"long. I would like to repair this problem if possible. Someone had mentioned to use "Weld On (I forgot the number) and attach a new piece of plexi-glass to the bottom, he also said that even if I glued the new piece on to the bottom the crack may continue to grow until it reaches the edge. <Yes... I'd plan on this... you can likely make a good repair by solventing (actually the process here... not gluing) another thinner sheet of acrylic onto the bottom of the existing one... over the crack and all else.> To remedy this problem I thought about drilling a small hole at the two ends of the crack to stop the crack from growing. Do you think this is a good idea? or do you have any other suggestions? I look forward to your input, <Do ask the folks at acrylic fabricating shops in your area, over the Net what they would do as well. I would solvent a piece onto the bottom and router off the edges. Bob Fenner> James

200 gallon tank (acrylic repair) <<Greetings,>> I was reading also something about drilling small holes on the bottom where the side and bottom connects and fill those holes with the #40 solvent along with sealing the inside of the tank; is that true???? <<I've never seen an acrylic tank built this way, although I can see why one might consider this stronger than a typical 90 degree joint. For certain, these holes would need to be precision drilled - too close to the outer edge, and the material will be weakened. Too close to the inner edge and the tank will likely leak. Cheers, J - >>

Re: 200 gallon tank (acrylic repair) When I push the side and bottom together, do I put the #40 glue <Not a glue... a solvent... melts the panel material together.> on the inside and the out side on the tank. Is the #40 better that the #3 and #16.Below is what I saw in the article on the web site... 1) Clean the wound. 2) Push the crack together. 3) Glue with #3 solvent to make a good seal. 4) See if the fracture extended into the sidewall and seal that if needed. <Depends on the width of the gap... if so wide you can actually see light through the space, a more viscous model would be better... In actual practice, it almost never matters... but if the gap area can be "squeezed" together by laying the tank on its side, placing a bunch of weight (finally a use for those encyclopedias!), I would do so. Bob Fenner>

Re: 200 gallon tank (acrylic repair) I did ask one of the people there and they told me it wouldn't work but if I was to use it I would need to inject it on with a syringe... <Please read over WetWebMedia.com using the search tool at the bottom of the homepage... with the terms "acrylic", "Plexiglas", "aquarium repair"... You need a version of the "whole picture" which you will not get by the current process. Bob Fenner>

Re: 200 gallon tank How do I put this stuff on, because I hear that it is some powerful stuff.... <Ask the folks you buy it from... read the label... not difficult. Bob F>

100 gallon tank (repair) I have a 100 gallon tank made by Acrylic Sea Clear Aquariums that is about 7 yrs old and the Silicone sealant has come off that separates the front and the bottom of the tank.  <Not made of silicone/silastic... these tanks are made by old friends of mine... of acrylic and solvent (Weld-On 40)> What suggestions do you have on getting this fixed, to have a professional person do it (do you have any suggested repair places) or do it myself and if so what produce should I use. I live in the Washington, DC area. <Actually, very easy to "do it yourself"... Look in your "Yellow Pages" phone directory of folks who retail Plexiglas, plastics... or do fabrication, and call, ask if they'll sell you a small amount of solvent. Clean up the joint, let it dry, and apply this material (with windows open on a nice breezy day or outside), let set for a day or so... fill up outside on top of a piece of newspaper (to test for leaks) and you're done! Bob Fenner> Thanks Glenn,

Re: 200 gallon acrylic tank repair Do you know if this Weld-On 40 stuff will work on a 200 gallon tank as well.... <Yes... this is what many (if not all) fabricators of acrylic aquariums use... for all sizes of systems. Bob Fenner>

Scratches on Acrylic Tanks Hi Bob, <Good morning! Steven Pro in this morning.> I have an old 125 gal. acrylic tank with scratches from rocks falling and coral pieces bumping into the tank. <A common problem with this material.> How do I remove the scratches? <There are various products on the market for buffing/polishing the acrylic to like new status.> The tank is empty now, <Which makes this procedure much easier.> and has been torn down for about a year. I would like to set it back up but I would like to try to make this tank look like new. Any information would be greatly appreciated. Thanks Kevin Shimabuku <Check out any of the dry goods e-tailers for acrylic repair/polishing kits. -Steven Pro>

Scratches (acrylic repair) Hi Bob, I have a 300 gallon acrylic reef tank that has a few scratches in it. I ordered some MicroMesh scratch remover pads from an acrylics shop on the web that can be used to "polish" out the scratches without using any scratch remover compound. Is it safe to use these polishing pads inside the tank to buff out the noticeable scratches in a small area ? <Yes... but does require that you lower the water level below the area to be smoothed out. Bob Fenner> Thanks, Chuck Spyropulos

Article on acrylic tanks Since you were so kind about my article on BTAs, I thought I'd point you to another article I did for someone else about my experience with a cracked acrylic tank. It is at http://www.canreef.com/library/acrylic_tank/acrylic_tanks.htm <http://www.canreef.com/library/acrylic_tank/acrylic_tanks.htm> and there are no copyright issues. If this looks like something you'd like, I can send you a zip with all the pictures. I could do another model of my new tank with the alternate cutout arrangement and larger corner rounds. <Sorry for the delay Marc. Have been and am in Australia (back 4/5). This does sound good. Will post and help you place on my return... saw your further sending but will have to wait... downloads, the Net is painfully slow here. Bob Fenner>

Article on acrylic tanks Hi, Bob, If you'd like to post this, do use the zip I sent in a later email. It is updated for content (and some typos). For better or worse, I have no more articles lurking around ;-). <Thanks Marc, will do so on return... soon> Hope you had a good trip and the post-trip email backlog isn't too daunting. <Am actually looking fwd to the effort (ask me a day or two into it...). Bob F> Marc

Article on cracked acrylic tank Hi, guys, You were kind about my BTA article so here's another one. If you like it, feel free to post it on WWM. This one is about my cracked acrylic tanks and what I learned about them while looking into this problem. The root file is acrylic_tanks.htm Marc <Marc... of all things I can't open this file... Can you send as an attached one in Word fmt, or paste onto Hotmail? Bob F>

Re: Article on cracked acrylic tank Marc, did find the link, the article. Posted: http://www.wetwebmedia.com/acrylicaqrepair.htm Do send this in (I would try FAMA first, let me know if you'd like help). Thank you for your input, sharing. Bob Fenner

Re: Article on cracked acrylic tank Bob, No problem; just fun with computers ;-). <Mmm, agreed today... a few days/weeks from now when the "just been out on dive travel" wears off I'll be more vinegary re Billy.G et co.> Looks like I somehow sent you my earlier version of the article. This one is fine although it has a few typos and it has a link to someone else's webpage (and I didn't confirm that it was okay to reference his page although I doubt that is a problem). I have another version with the typos corrected and the link reference removed. If you'd like it, let me know. <Okay either way> Glad you liked. Let me know if I can help with anything. Don't claim to be an expert but I can do 3D models of stuff for you if you like (as long as it doesn't involve living things, it is pretty easy for me) and as for another article, I've been toying with a "things I learned the hard way" article. Marc <These are very popular, useful. Hope to see you producing more and enjoying the "big fame" and small dollars from their publication... and the almost all-consuming satisfaction of knowing you have helped others. Bob Fenner>