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Related FAQs: Silicone/Sealant/Sealing 1, Silicone/Sealant 3, Silicone/Sealant 4, Silicone/Sealant 5, Silicone/Sealant 6, & Glass Aquarium Repair 1, Glass Aquarium Repair 2, G lass Aquarium Repair 3, Glass Aquarium Repair 4, Glass Aquarium Repair 5,  & FAQs on Repairing Glass Tank: Scratches/Blemishes, Cross-Braces, Leaks, Chips/Cracks, Whole Panes, Tools: Cutting Glass, Moulding/Frames; Techniques; Olde Tank (Slate Bottom, Metal Frame, Pecora...) Repairs, Troubleshooting/Repairs, & Acrylic Aquarium RepairUsed Aquarium Gear

Re: Emergency! chipped corner, PROBLEM WITH NEW TANK   9/19/08 Mr. Fenner, I can't believe I'm writing you again, I'm trying not to cry. We did get a new tank, taller than our old one. We got it set up and moved all the rocks and livestock in it the night before last, though we were short about twenty gallons and ran the system not fully filled. Last night we added the rest of the water. This morning, I see some kind of bubble (I guess) on the corner, somewhere between halfway and two thirds up from the bottom. I am positive that it was not there before. I had noticed something a little funky in that spot, but I thought it was just a little excess sealant on the outside, the actual seal between the two panes looked completely fine to me. (I know we're supposed to fill a new tank and observe for leaks before adding livestock, but time and manpower was an issue; a big mistake, I know). I've already drained the water down to about where the "bubble" is (is that sufficient?), and have powerheads running in the tank with the rocks and livestock. <Mmm, see below> I don't really understand what I'm seeing. It looks like the problem is not in the seam per se, but on the side edge of the front panel. I'm attaching three pics. The first one is taken looking at it directly from the front. The second one is looking at it from the side (at kind of a funny angle so the light would get it right). The third is taken from the front, looking at it diagonally. I think I know what you are going to say. (That we have to drain all the water, put it all and the rock and livestock into countless bins with powerheads; take this tank back to the store, get our friend to help us again move this tank and another new one, fill it in the garage first with fresh water, observe it for a day, then drain it, move it into the house and set it up...the thought of all this makes me want to have a nervous breakdown... Go ahead, Mr. Fenner, put "the fear of Bob" onto me... Elise <Actually, this defect is not likely problematical at all. If this tank were mine, I'd go ahead and leave it set up. Though the one "whitish" seam is not "all that great" (there was a bit too much gap twixt the panels when Silastic was applied), this vacuolation won't likely lead to failure. Bob Fenner>

Re: Emergency! chipped corner, PROBLEM WITH NEW TANK   9/19/08 Really??? Holy cow, I can't describe how happy you just made me. I shouldn't be alarmed, then, that this "thing" appeared after the tank was full, and was definitely not there before? <Mmm, no, or at least "not very"... such bubbles are quite common... Unless the tank has "just been made" (in the last days, week...) they're not problematical unless too large (spanning the joint let's say)> Thanks, thanks, thanks so much and thanks for the very speedy response! What, are you sitting at your computer waiting for me to write you with all my problems? Tee-hee! Elise <May seem so. Usually I "wait" till next day, try to respond to what others here have not done so, so that I learn content, format... but folks who are apparently in distress, I will "jump ahead" on. BobF> 

Issue or not? My new 240 has mystery bubble/chip in glass Pics included  8/19/08 Hi crew, So I got this tank setup a couple of weeks ago. I had it built in Early July, picked up on the 10th or so of July. Filled it up on August 6 I believe. There is a photo before where it doesn't show the bubble and now where you can and some close up shots. It is on the inside of the tank as if there was a chip on the side that was not noticed when dry. Now that there is water in it, it has shown up. I can not feel it from the inside of the tank when pressing on the sealant. What should I do? Have you guys seen this before? <The bubbling does show up over time at times... either from forces "pulling" the gas into larger view/size, sometimes from microbial involvement (metabolism). I would do nothing re it. The chip here is worrisome... something struck inward of this panel at an obtuse angle... If you live in an area where the ground shakes, I would take this tank down, Silicone a panel of glass of some size over this area on the outside of the tank, turns this panel to the wall. (Use the other side as the front). Bob Fenner>

Resealing Used 55 07/28/2008 WWM Crew: I bought a used 55 gallon that I found to have a leak. I've been all over the WWM site, and already know what needs to be done. This tank is a work in progress since I will not be putting it up until our next military move at the end of 2009. I have time. However, I have been told by two hobbyists that I cannot reseal unless I plan on having water in the tank within a year's time. <... incorrect> They are saying that I will have to reseal and that I have been lucky to have dry tanks usable after 2 years. <... No> I have been using Google and checking this site today, I haven't found anything to substantiate this claim yet. <There is no such substantiation. They're wrong> If this is indeed the case, then I can wait several months before messing with it. If not, is there an interesting historical tale I can run back and relate to these hobbyists? <Am feeling so old today that I'll consider myself as such... have them contact me, or Dow Corning re Silastic applications if they're so inclined... Now, back to work in the real world to generate GDP. BobF> Thank You, Becky C

Bonding Acrylic to Glass 7/17/08 HI there, <Hello.> Hope you're having a good day. I wanted to know what's the best thing to glue acrylic to glass? I have a glass aquarium and I want to build external coast-to-coast on it using acrylic. Can you please help me? <You could use a two part epoxy gel such as 5 min epoxy, although I would not. For an external overflow do consider using glass and silicone, this will make a much more reliable bond to keep water off your floor!> Thanks Ghazni <Welcome, Scott V.>

125 gallon glass aquarium, sealant good?  06/24/2008 Hello to all! <<Morning, Andrew today>> Sorry for the first message, somehow I managed to send it with just a few words! <<its fine, we are here now>> I have a question regarding a used 125 gallon aquarium that I just purchased. I got it at a steal and was just wondering what kinds of things I should look at as far as signs of silicone failure. The tank is different from what I am used to seeing. It is 1/2" glass with a 3/8" glass brace in the center on top. The trim is wood grain but instead of being flat like most, it tapers as it goes down the side. I am trying to figure out what brand this thing is. The only sticker I can find on it has FM which is bold lettering, like a stamp then it has the date, May 30, 1999 and a serial number...Maybe someone is familiar? Thanks for your time and keep up the good work on the site. <<Not a tank make i am familiar with, unless its referring to "Fauna Marin". As to your questions on what to look for. Look for browning silicone, splits and lifting, bubbles between the glass joints are indicative of poor silicon and bad joints. The main thing i look for to start with, is browning silicon. Please do read more here http://www.wetwebmedia.com/aqrepairfaqs.htm including linked articles and FAQ's >> Jacob <<Thanks for the questions, hope this helps. A Nixon>>

125 gal tank about to pop?   6/12/08 Hi, I have a 125 gal tank, no idea how old it is. We bought it used. I would guess around 10 yrs or so. Anyway we just set it up about a week ago. I noticed after we added water all the way to the top that the front panel on the right looked as if it was pulling away from the panel on the side. <!?> On the left side the silicon is clear and has no air bubbles in it. On the right it has large air bubbles and is cloudy looking. So far there is no leak, but we did drop the water level to half for now. The tank houses 2 4 inch sliders and several feeder fish. I think the turtles will be fine for know, but I am unsure how to fix the problem. <... posted> Do I need to empty the tank and completely take it apart and put it back together? <One approach... however... IF the tank is holding together, and you're happy/satisfied with it partly filled...> And how on earth would I go about doing that? Or could I just empty it and take the silicone off the inside of that corner and replace it, and try to push some into the gap were it is pulling away? Would it stand any chance of holding? I have to say I am very worried, as I would not like a pond in my living room. Please any help is greatly appreciated. <Here: http://wetwebmedia.com/marine/maintenance/index.htm about the sixth tray down... Aquarium Repair... Bob Fenner>

Re: 125 gal tank about to pop? 6/12/08 Hi, me again. I looked at all the stories there, <Stories?> but was unable to find one that answered my specific questions. I would like to have a full tank as my sliders really like the space. <... need room to get out of the water as well...> But I am not sure about the seam. Can I empty the tank, scrape off all the corner silicone and clean out silicone between the 2 panels on just that side? <Nope> If so how far down and how to reseal the new silicone to the bottom old silicone? Could I reseal by pushing new silicone in between the panels and then reseal the corner inside? Or do I need to take all the inside silicone off and the side that has pulled away and start from there? Will it hold? Please help!! Thank you> <Read those stories again... IF you decide to re-silicone this tank, all panels will need to be disassembled... it will do no good to just Silicone in the corners... this material is almost non-functional structurally. BobF>

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

Tank Compromised? Seal...   2/22/08 Hi! <Hello there> I'm happy that I stumbled across your website. I'm just getting into marine aquaria and it has answered numerous questions that I have had and, I'm sure, will answer countless more in the future. <Sounds good> On to the issue at hand. My initial purchase was from an associate who had a reef aquarium set up. He is moving and cannot bring it along. The purchase was for an all-glass 72 gallon bow front (non-drilled) aquarium along with the stand, a nice light set, a protein skimmer, a wet/dry sump, numerous pumps blah, blah, blah... He bought the set up new but I'm not sure how long ago. Basically, I got the entire package for $400. He informed me that the silicone seals in the tank were turning color (possibly from oxidation) <Mmmm> and some of the seals may need to be re-siliconed (pictures attached). <I see them> It does, however, hold water. I still purchased the set up simply because the other stuff that was included in the package was well worth the $400 even if I have to purchase a new tank. <Okay> So anyway, after a closer look at the seams in the tank I noticed that the front left seam toward the bottom was actually turning white (the initial color of the silicone was black). I reached into the tank to feel the silicone and it was somewhat brittle as expected. <Yes...> After reading much of the information on WWM about resealing/repairing tanks I took a razor blade and carefully removed the silicone that is on the inside of the glass (not between the glass joints). For the most part the silicone that is between the glass joints looks intact (I'm assuming that it should be approximately the same thickness as the glass that it is sealing) except for the front left corner near the bottom. That seal still looks white. I am concerned about this because I wouldn't want to get the system up and running and spring a leak a week later. <I agree with, share this concern> So, would I be correct in assuming that I need to reseal the tank? (genius, I know...) Also, I have read different accounts about resealing tanks (or maybe I have simply misinterpreted what I've read). It appears as if in some cases the silicone that is inside the tank, but not directly between the joints, can be carefully removed and replaced provided the seam between the actual glass panels is left unharmed. In other cases I see that a single panel can be removed and resealed. Then there are the accounts of taking the entire tank down, removing all of the silicone and replacing all of the panels with new seals. <Mmmm, well... the Silastic "not between the glass" is actually mostly non-functional in terms of holding the panels together (this is done almost completely by the small amount between the panels... The bit in the corners is really there basically to keep tools from getting into the real seal...> I'm thinking that since the silicone issue in the front left bottom part of the tank is so extensive I'll have to repair that but I'm not sure about the rest of the tank and the rest of the seams. <... Not realistic... If taking the one panel apart, the rest should be done... and IS a job for sure...> Also, I have seen other tanks with the black silicone that also have the issue where the silicone turns yellow/white. Is this common with the black silicone or does it happen to all silicone and the contrast to the original black color makes it so noticeable? <Does happen with some "batches" of Silastic... but not all. I have some European made units (most lack the "extra" corner beads entirely) and they are fine after decades of use...> Anyway, thanks for any help/info that you can suggest. Dave <Basically three choices, go with the tank as it is now (not advised), try to fix by taking apart and re-sealing (much time, lots of single-edged razor blades), or seek out, buy a new tank/replacement (which is what I would do), leaving this old one to turn into a paludarium, some other not-totally water filled function... Up to you. Bob Fenner>

Fish Tank Sealant Question 1/12/08 Hi! <Etta> I have looked through your site and have not found an answer to my question. I need to seal one of my 10G fresh water fish tanks. I had mice in it and now want to convert it back to have fish in it. The only problem is they have chewed the bottom corners of the sealant and it needs to be replaced. I just wanted to know the difference between a regular 100% white silicon sealant or regular clear 100% fish tank sealant and what to use. I have some regular hanging around the house but wanted to know if it would kill my fish before I use it. <100% silicone is all you need. Just be sure it is truly 100%, no mildewcides and the such. The white can work if it is 100% silicone, but it will be kind of unsightly.> Thank you! Please reply. -Etta <Welcome, Scott V.>

Custom frameless tank   1/11/08 Hi, <Sandy> I just purchased a custom size frameless 125 gallon tank from Lee-Mar. When I received the tank there were numerous air bubbles in the silicone there the panels are joined, I don't mean just little bubbles, I mean large areas that look like a worm crawled though the sealant. They are on all the seams, side, and bottom. The tank was built using ¾ inch Starfire glass and I am concerned with the tanks ability to "stand the test of time". Any thoughts? Thanks! Sandy <Very unusual to hear/read of such apparently sloppy workmanship by Lee Mar... I have known the old owner and now his sons who run the company for decades... and usually the company's craftsmanship is superb. I would take some digital pix and send them to the management... And to me/us as well... IF these vacuolations are not too numerous, nor too interconnected, there should be no problem going forward... Bob Fenner>

Re: Custom frameless tank 1/12/2008 Thank you so much for your assistance! We did get a hold of Lee-Mar yesterday, and they, as you, seemed to be surprised that this tank passed quality control, based on the photo's and descriptions of the tank. <Ah, excellent> They are going to take the tank apart and re-do it. Your prompt response and advice was much appreciated. I look forward to a new tank and visiting your site often. Sandy Moats <Thank you for this follow-up. Bob Fenner>

Aquarium joint too large.. and leaking. 7/9/07 Hello, I received a leaking 36x18x24" 65 gallon aquarium. It is of the recessed bottom variety, where the bottom panel meets the side panels on their insides, rather than the side panels sitting on top of the bottom (hope that makes sense). <Yes, it does...> After removing the old bottom seal, I could see that this bottom panel appeared to be a bit too small. On three sides there is a 1/16" or smaller gap between itself and its adjacent side panel. On the fourth side (long), this gap is 1/4" and filled with more silicone sealant (photo attached). <Yikes... MUCH too large> It's not in great shape and has some gouges, slits, etc. It originally leaked somewhere out of this side. Since the gap is so large, I know I can't make a proper glass to glass seal over it (already tried, holds up until aquarium is almost full, then leaks.) <Correct> Based on what I've read here, my first thought was to have a 36 inch strip of glass cut. I would shove it into the length of this side so that it overlaps this 1/4" gap by an inch or two, then seal it in place. <Yes> Does this seem like a good idea, or am I looking at a terrarium here? Thanks, Eric Dreyer <This is what I would do as well. Take your time cutting away the old Silicone, cleaning the area with a solvent. Bob Fenner>

Re: Aquarium joint too large.. and leaking.  -- 10/30/2007 This is an update to a question I posed about 4 months ago. I wanted to have my success posted in case anyone else might run into a similar problem. The interior length of the tank was 35 7/8", so I had a piece of glass cut -- 35 13/16" x 2" x 1/4" thick. The first time around I simply placed the glass in the tank and siliconed anywhere glass met glass. The tank leaked, and the weight of the water actually cracked the glass (must have not been completely flush with the bottom.) <Mmm, yes... needs to be nestled... oh, I see this below> I had a second piece cut and applied silicone to the entire surface of that piece before laying it down. I carefully pressed the glass as far down and into the corner as it would go. Then I applied silicone as usual to all glass to glass seams and weighed it down. No leaks in 3+ months. Thanks for your help; this site is a terrific resource. <Ah! Congrats! Cheers, Bob Fenner>

Glass tank seam bubbles 10/16/07 Hi, <Hello there> I just bought a 29 gallon for a salt set-up and I have two questions. First, I've attached pics of what I think may be a bunch of tiny bubble leaks on a seam. I'm really not sure if it's even air in there because it just looks like a haze. <Do look like air bubbles> The tank holds water. Do you think this is a problem? I realize that if the glass shifts there could be leaks, but couldn't a shift even cause leaks in a perfect seal? <Shifts? Is worrisome to me... are these bubbles a recent advent?> Second question, I want a snowflake eel. Will keeping it in the 29 gallon be ok? <No... this is too small a space/volume> How fast do they grow? Is there a way to ensure that I get a smaller eel? Will it grow less in this size tank? Thanks bunches. ; ) <... better to look to other species. If this were my tank, and it was new... w/in warranty, I'd trade it in for a replacement. Bob Fenner>

Re: Glass tank seam bubbles 10/16/07 Thanks for the reply, The bubbles are not recent as far as I know. I just bought the tank and this is how it came. I was really trying to avoid breaking it down, but if you think it could be a problem I'll do it. <I definitely am concerned sufficiently to mention what I would do here. When the seam is more than half bubbled across... this can be trouble. Bob Fenner>

55 Gallon Aquarium Questions... reseal job?    9/25/07 Hello, <Darin> I received a used 55 gallon glass aquarium (rectangular), here are the particulars: Built in 1990 Has not held water for 5 years Silicone on inside seams is fraying/pealing up from glass <How badly? Can you send pix?> Not reported to have leaked prior to being put in storage Was used for salt water set up (I want to go with fresh water) I figure it will probably leak if I fill it with water and I plan to reseal the tank. Can I just remove the old silicone at the seams with a razor blade, wipe with acetone and reseal without removing the silicone between the glass panes? <Removing... between the panels as well? And replacing this? Yes, if this is what you deem necessary... This tank could be tested (outdoors, the garage) over newspaper... on the intended stand... first...> I have been trying to read the FAQs and was getting a little confused about the proper guidance for this. <Help me make this more clear> I received an oak stand and hood with it as well, <How nice!> that I have been repainting (Kilz and white high gloss paint - there was mold and mildew on it from storage). The stand appears to be level and the place in my house where I will place it is level (basement with cement slab). <Good> Is the paint going to be alright on the hood? - I started to get worried about condensation off the frame and it dripping into the tank. <Should be fine once thoroughly dried> Should I still put foam underneath my tank (between tank and oak board) or is this not necessary if all is level? Does the foam help prevent torsion? <Actually only to a very small extent, depending on the "body", density of the material. Should NOT be counted on to make more than a credit card's difference> Many thanks, Darin <Do test the tank and please send along some close up images of areas that are of concern. Bob Fenner>

Re: 55 Gallon Aquarium Questions... Reseal job, yes 9/26/07 Hi- <Greetings again> Many thanks for the response and answers - here are some pics of the inner seal of the tank. You can see the edge is frayed and chopped out and is pealing/lifting at the edge (all four corners are like this). <I see this> Unfortunately I have not had a chance yet to fill it and test for leaks. Even if it does not leak I think for cleaning this issue will also be a problem, algae could grow underneath the lifted off portion of silicone. <Yes> Scrubbing it will just remove more silicone I fear. Cosmetically it also is an issue I think. <Agreed...> So I was just going to remove the inner silicone and reseal and not remove the seal between the glass panes. <I do agree with this path. Is what I would do as well> Is this right? Otherwise if I had to also remove the seal between the panes and reseal I think it will be too much effort with an uncertain reward and I will probably just purchase a new tank. <Agreed here too> I thought I had read some guidance on your site that said to do both inner and the in-between pane seals when resealing a tank, as well as guidance to just remove the inner seal and reseal. That is where I got somewhat confused and concerned about what to do. I may have read it wrong or got it out of context perhaps. <Either route is prudent depending on the perceived value of improvement. In this/your case, having seen the seals, I think the functional/tween glass Silastic is likely fine... but the aesthetic corner beads are shot...> Your guidance is greatly appreciated! Cheers, Darin <Mmm... I would look into black or clear Silastic, 100 % of course... practice with... Use a tongue depressor, clothes pin or such to smooth the bead... trim (lots of single edge razor blades...). Covered on WWM. Bob Fenner>

Wrong Silicone! -- 09/05/07 Hello! <<Hi there!>> Kind of panicking a little bit here. <<Oh?>> After doing some research, but apparently not enough, I set up a sump/refugium for my system. <<Cool!>> I installed the baffles with GE Silicone II. <<Mmm, not 100% silicone...contains modifiers to make it paintable and biocides to reduce mold/mildew>> The silicone cured for 48 hrs + before being used, and then used for a little less than 12 hrs before I discovered that this was not an appropriate product. <<Indeed>> Fish look ok now, but do have a couple of corals that do not look normal. Do you think I'm just overreacting at this point or do I have a real problem and do I need to do anything other than just change the type of silicone on the baffles? <<I would remove and replace with an appropriate Silastic silicone rubber. You could even forgo the sealant altogether and use 'pressure-lock' baffles as explained here (http://www.wetwebmedia.com/ca/volume_3/cav3i1/Baffles/baffles.htm). Either way you go...add some carbon/Poly-Filter to help remove any possible contaminants from the Silicone II product and all will likely be fine>> Thank you so much for your wealth of info. Ryan <<Happy to assist. EricR>>

White seams     7/25/07 Hello all. I have not seen this on any posts on this yet from when I searched so I thought I would ask. I am currently building about a 150g all glass. Dimensions are 24x24x60, I used 1/2" plate glass. The silicone I used was GE RTV108. From the research I did that is the same stuff tank manufactures use. <Some do> I started filling it and found no problems until it was about 3/4 the way full then the seams along the top of the tank started to turn a little white, after it was as full as my overflows would allow, the white in the seams never grew in size. <Mmmm... how long did you allow for this Silicone to cure?> I emptied it and did more researching on the subject. I went and tried to pull the front pane of glass from the sides to see how well they were siliconed together, then I noticed that it turned white in the same place as when I filled it with water. So that tells me that the water is not getting in the seam turning it white, but when the seam stretches a little is what does it. Do you think from your experience that this will be an issue down the road if I just use it as is? <Is this "only" at/near the surface? That is, an area where there is not much force?> There is a few 0.5-1mm bubbles from when I siliconed it together but they haven't changed size or turned white. <Good> Thanks for the help and the web site. Chris <If there is no further "whitening", and the section where there is has not much structural function I would not be overly concerned. Bob Fenner>

Re: white seams   8/26/07 > Hello all. > I have not seen this on any posts on this yet from when I searched so I thought I would ask. > I am currently building about a 150g all glass. Dimensions are 24x24x60, I used 1/2" plate glass. > The silicone I used was GE RTV108. From the research I did that is the same stuff tank manufactures use. > <Some do> > I started filling it and found no problems until it was about 3/4 the way full then the seams along the top of the tank > started to turn a little white, after it was as full as my overflows would allow, the white in the seams never grew in size. > <Mmmm... how long did you allow for this Silicone to cure?> About 7-9 days before it was filled - with two jobs I didn't have time to rush it :) <<This is a good long while... should have been thoroughly cured... I suspect there was a "bad spot" in the filling, making of the one area of the given RTV>> > I emptied it and did more researching on the subject. > I went and tried to pull the front pane of glass from the sides to see how well they were siliconed together, then I noticed > that it turned white in the same place as when I filled it with water. > So that tells me that the water is not getting in the seam turning it white, but when the seam stretches a little is what does it. > Do you think from your experience that this will be an issue down the road if I just use it as is? > <Is this "only" at/near the surface? That is, an area where there is not much force?> The white spot is only along the top side 4" down from the top of the tank near the center of the seam which is 1/2" |--------| ^ about here, it extends about 3/4 inch long <<I see... again, this should be fine>> > There is a few 0.5-1mm bubbles from when I siliconed it together but they haven't changed size or turned white. > <Good> > Thanks for the help and the web site. > Chris > <If there is no further "whitening", and the section where there is has not much structural function I would not be overly concerned. Bob Fenner> All of the lower seams never have changed, so I think that they would hold fine, but I did not leave water in it very long because of the mentioned from above. <<I see... I would test fill this "outside" (maybe a garage) and leave for a week or so to further observe>> Also when reading other posts and pages they talk about the seams turning chalk white, is that from when water is getting into them or is it just from the pressure of the water pulling them? <<The water intruding into imperfectly made (too thick) areas of the Silastic that have not cured. RMF>> Thanks for the help and reply Chris

Silicone lifting in 20gal  8/16/07 I have a 1995 model 20 gallon All-Glass tank that was in use for many years with no problems. It spent the last year and a half in the attic, but now I'm hoping to resurrect it in my new apartment. I cleaned it up and tested it, and it continues to be leak-free. The silicone on the inside feels soft and like new, but in one spot along the bottom is lifting and bubbling. <Interesting... I would bet that this was as it was originally constructed. Few influences (time, heat, chemicals...) can change Silastic thus> As I am now living in a second floor apartment with other tenants below me, I'm completely paranoid about springing a leak. Should I scrape out the old silicone and reseal it, or is it best to leave well enough alone? Courtney <If it were me, knowing what I know, what you've related, I would use this tank as is. More likely to be problems from trying to re-do. Cheers, Bob Fenner>

Re: silicone lifting in 20gal  8/16/07 Thanks for the quick reply. I will leave the tank another day or two with water to be sure there are no slow leaks, and then I'll go ahead with setup. <Good plan. BobF>

Replace black sealant in 47 gallon aquarium?  8/2/07 I am looking to sell my 6 year old, 47 gallon bow front aquarium. After cleaning it out, I noticed that the black seal on the inside of the tank is peeling in some areas, however it is not leaking as of yet. I was wondering if I should replace the seal before selling the aquarium, or do you think it will be ok if I don't? I have included 2 pics of the peeling sealant. Thanks! Amy <Mmm... I might try first selling this tank "as is"... the exposed Silastic is not really a functional part of the seal, but more to prevent folks from slicing into the between-glass bond... If the purchaser wants to replace it/this, let them. Bob Fenner>

Silicone/Acrylic bond... not great... CPR unit?  -- 06/26/07 Hi Bob! Thanks in advance for your response. I am starting up a nano set up at work. I have purchased a 16 gallon acrylic tank that is made by CPR, but sold online under a different label. It has a great skimmer and looks really nice. I am currently cycling the lank with live rock and live sand. However, I am a little concerned because the retrofit light kits appear to be attached to the acrylic hood using silicone. While there is not much weight involved, you mention frequently on your site (which is an amazing site) that you do not have much faith in the adhesion qualities of silicone to acrylic, and I would really appreciate your view of whether or not this use represents a potential hazard. In other words, even if there is not much weight involved, could the heat of the lights or some other factor weaken the bond and result in my lights falling into the tank? I would really appreciate your thoughts on this. Thanks very much, Lindsey. <Mmm, I too am concerned... but I do know and trust the owner of CPR (Suk Chu Kim)... am BCC'g him here for input re... otherwise, do please contact him, them at: http://www.cpraquatic.com/index2.html

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