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FAQs on Glass Aquarium Repair, Silicone/Silastic... Aquarium- Use 100% (Aquarium Use) ONLY, 5 

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Tank Seam Question       8/9/14
Dear WetWebMedia,
I am hoping you can give me some advice on a situation I am having. I had a custom aquarium built which is 50 gallons 36"x18"x18" rimless with a Starfire front using 3/8" glass. Upon filling it up the first time I noticed there were stretch marks appearing in the silicone. This alarmed me and some people I have spoken to said it would be cause for concern. It was showing in the front two seams. I had the builder tank <take> the tank back and had it redone. After picking it up after the redo I was filling it again
and noticed these stretch marks appearing again. However this time only in the front right side. Upon taking someone's advice I have added 4 glass triangles to help create a brace for the top of the tank and added an extra bead of silicone to the inside seam creating a wider seal.(you can see in pic my sloppy job). After doing these modifications I am still seeing these stretch marks in the front right seam, not as bad but still enough to worry me.
I've tried searching for similar things and only on your sites have I come across similar pics but not exactly what I am seeing. The builder insists these are normal and will go away in a few days but I honestly don't believe that. He will not give me my money back for the aquarium.
In your opinion Is this a serious problem or will it be okay?
<Though not pretty, I do think (w/ high confidence) you will be okay here>
Some people I have spoken with said it would be fine since the tank is small but I don't feel safe about it. Can you please give me your opinion.
Sorry for the long email but wanted to explain everything.
Thank you
<Welcome. Bob Fenner>


White slim... film?  Tank-Re-Siliconing concern       7/17/14
I have a tank I just had resealed by a company that has been doing it for 15 years, has a long list of customer on local forum I contacted for reference first. The tank cured about a month before I was ready to add water. Well I'm cycling the tank and have a weird white slim that seems to be growing on just the silicone seams. There is no skimmer running right now, just a power head for water movement, doing a fish less cycle with ammonium chloride. If i run my finger down the seam the slim easily comes off and floats in little pieces. See pictures attached, I ran my finger down to show difference with and without slim. Marine set up with live aragonite and base rock.
Thank you very much.
<... So? Have you contacted the repair company? Wish I had a sample of the slim/film to look at under a 'scope. Am wondering what sort of solvent they used to clean up the glass right ahead of the reseal... The rest of the Silastic appears to be in good shape. Bob Fenner>

Re: White slim      7/17/14
I have contacted them and other that have had their tank
<Is this English?>
redone and no one has reported that problem. If you lived close I'd get your a sample in a heart beat. I could check on shipping.
I will calk and ask what silicone they used.
<Real good.
Re: White slim

Used model 33sc
<Uhh; see WWM re Silastic Sealant use for aquariums.
This one: "Limitations - It is not recommended for structural glazing or insulating glass glazing, "

... B>

Re: White slim... the price of...       7/18/14
What's your address and I can see how much shipping would be. I'm more curious than anything now.
<... Read here: http://wetwebmedia.com/glstksilasticF5.htm

and the linked files above>

Growing Brown Streaks in Silicone    2/18/14
Odd one here.  I have enlarging (by the day) brown streaks in the black silicone of my 2 year old 120 gal reef tank.
<I see these... mold/mould... not good>
Please see pictures, any idea what this is and if it will compromise the integrity of the tank?
<Indeed it will>
For clarification, please look directly above the Vortech equipment at the black strip of silicone, there is a 3" area that has turned streaky and brown, this area spans the width of the silicone.  The other pictures are of the same color streak from the front and side view of the aquarium (been taping and watching this one grow 1/4"-1/2" per day).
<This tank needs to be taken down; the olde Silastic cut away, the glass surfaces cleaned... And re-done. Quite a bit re this archived on WWM. Bob Fenner>

Aquarium seal problem?      2/15/14
First, let me thank you for your help. 
Brought home new 29 gallon Marineland glass aquarium.  Filled tank, and "bubbles"(?) appeared after filling; all seams appeared to have the same problem. See photo 1. what is this problem, could the water have been to<o> cold (Tap water 55 degrees F)?
 When we drained the tank, bubbles went away:  See photo 2.  Is this tank going to leak?
<Possibly; or worse>
 Is it worth keeping, or should i return it?
<I would definitely return this tank. Years back there were incidents of "bad black Silastic"... that looked like this. Trouble>
What do you think?
<Defective material>
Thanks again,
<Welcome. Thank you for sharing. Bob Fenner>

Water mould on used tank     2/5/14
Hello Crew!
I've always relied on WWM when I have questions so here I am again:)
I have a 3 inch GSP living in SG1.009 brackish environment. It has been living in a 20gallon, and I finally have a 31gallon tank for him! Due to my tight budget, I had to get a used tank. It is a really sturdy tank that was used for 3 years to contain 6 parrot fish.
The tank is curved on the front, so no silicon on the two corners. It has silicon inside and out,
<Out? Moan...>

 but what worries me is that there is black mould on the silicon on the inside of the tank. A little frayed as well. Either the tank is a lot older than 3 years or the silicon job was done poorly in the first place.
I wiped the surface the best I could, and the silicon linings seem half cleaner now. Have done water test two times, no leak. What should I do?
<Next time it's empty completely try a light (chlorine) bleaching... with the windows open>
Will it be harmful for my GSP?
<Not likely; no>
Should I take out the old one and re-silicon?
<I wouldn't... too much trouble/work... likelihood of not improving the situation>
Just that I have no experience, and the nearby LFS are all inexperienced when it comes to this. Will it be alright after I give it a thorough wash with white vinegar?
<I'd go the bleach route first>
Thanks in advance, June.
<Welcome. Bob Fenner>

93 gallon rimless cube - seam concerns    1/10/14
Hey guys! I wanted to run this by you to see what you thought. I have purchased a new 93 gallon rimless cube and have noticed one of the seams do not look right. I am concerned if I fill it (still dry), I will have to  have my livestock/floor replaced. Any help is appreciated! Thanks for what you do!
<You'll likely be fine here... though sloppy, the imperfect seam area is at least near the top. Bob Fenner>

Black silicone turning orange. Replace?     11/24/13
Hello wonderful WetWeb people!  It has been several years since my last query to you, and I'm hoping you will indulge a repetitive question. I would like an experienced opinion on a 54 gallon corner Aqueon tank I just purchased used. There is a similar query with pictures dated 8/2/07 on http://wetwebmedia.com/glstksilasticf2.htm (second to the bottom).  The black silicone on my used corner tank is similarly discolored, though not lifted in any way (hopefully the pictures come through below).
It holds water without leaking. Should I re-silicone this tank?
<Yes; I would. I've found that this orange discoloration goes with a degrading of seals>
 Thank you very much for your opinion and for all the time you and the others contribute to this über valuable site.
-- Carolyn
<Cheers! Bob Fenner>

Re: Black silicone turning orange. Replace?     11/24/13
Me. Fenner,
    Thank you kindly for your reply. I am wondering if I need to reseal the back corner behind the overflow, as it appears that the overflow creates two "continuous beads" (one in front - within the main tank, and one behind the overflow in the corner).
<The overflow seals (inside the tank) aren't important, but any leading to the outside are>
  I also am hoping that it is sufficient to reseal the inner silicone without disturbing the silicone between the panes. Could you please advise me regarding those two points?
<I'd cut away the bad part of the internal seal... and IF the twixt glass part looks okay, just replace the corner seal>
Again, I thank you for being willing to revisit this subject again (and again).
Sincerely (and gratefully!),
-- Carolyn
<Welcome. BobF>
Re: Black silicone turning orange. Replace?     11/25/13

Thank you, Mr. Fenner.  I have to say, I am slightly star struck that it is You who answered my query!
Your writing initiated me into this hobby, and I can not thank you enough. Thank you again for your time, patience, expertise, and willingness.
-- Carolyn
<A pleasure to share Carolyn. B>

bubbling in aquarium seams. Do-overs   9/14/13
So i just bought some custom made frag tanks  made to my specifications.
received them today and they look good but the seams are far from perfect,
<I'll say>

 I'm not bothered about how it looks they are just frag tanks i just want to know if they are safe.  the dimensions are around 90cm by 90cm and 45cm high made from 8mm glass, Eurobraced (got 3 of these).
when i saw the bubbling i did mention to the guy delivering the tanks if that was ok and he said it was fine and they guy who makes them uses a marine silicone which he says is stronger than normal silicone. these guy are  a legit company and have a website and are on eBay so i think they sell quite a few tanks so I don't think they would sell me tanks that are faulty?
<I would hope not, but... honestly (the only way I can be), I wouldn't accept these... too poor workmanship...>
so I've attached some pictures of a few bubbling points but there are more that's not in the pictures. (one of the pictures is from the bottom corner looking up through the base plate, this seems to be the worst one)
also where they drilled the holes they have chipped the hole quite badly
<And this... amateurish...>
 and was wondering what your thoughts are on that (picture attached) thanks for your time, rob
<I'd let these folks do these again. Bob Fenner>

Re: bubbling in aquarium seams   9/14/13
I got these tanks pretty cheap around £140 each guess you get what you pay for but i won't pay for tanks that will fail and flood my garage, do you think the seams will fail, i can attach more pics if you need. thanks rob
<I don't think these tanks will fail at the seams, nor about the bad through put holes... they're just not "up to snuff" in terms of quality of construction. BobF>
RE: bubbling in aquarium seams   9/15/13

Hi bob . i
<Rob/rob, do run your writing through a grammar/spell checker>
seem to be really unlucky with tanks, don't know if you remember the last time I was on here asking for advice i got some tanks (3 6ft tanks) all three had too be taken apart and built again because there was little to no silicone between the seams,
<Actually, the less here the better>
it was painstaking. and set me back a couple of years on my frag tanks project. I think I'm going to keep the tanks. I'm a bit disappointed in the craftsmanship but as long as they hold the water safely then that's good enough for me as I just want to get the ball rolling.
thanks for the replies and the advice,  rob.
<Real good. As stated, these "just look bad"; but will likely not fail leak wise. B>
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