FAQs on Glass Aquarium Repair, Chips/Cracks
Related Articles: Aquarium
Repair, Acrylic Aquarium
Aquariums, Marine Tanks, Stands and
Covers, Used Gear for Marine
Systems, Designer Marine tanks,
stands and covers,
Related FAQs: Chips/Cracks 1, Chips/Cracks 2,
3, Chips/Cracks 4,
Chips/Cracks 6, Chips/Cracks 7,
Chips/Cracks 9, Chips/Cracks 10,
& 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, Whole
Panes, Tools: Cutting Glass,
Silicone, Moulding/Frames; Techniques; Olde Tank (Slate Bottom, Metal Frame,
Pecora...) Repairs, Troubleshooting/Repairs, &
Repair, Used Aquarium
Chip in Fish Tank and Cracks in plastic
I just bought a 125 gallon fish tank off craigslist after wanting
to upgrade from my 55 gallon. Between the stand, the tank, and
everything that came with it, it was a complete steal. But of
course, as usual, you don't find things that are wrong with
it until you get home, or it happens in the transit....
There is a chip on the corner of the tank...sad face. The glass
is about 1 cm thick and the chip is on the back panel. I am
attaching pictures and I hope that you can see well enough to see
what is going on in the pictures, however with the dark color of
where the glass joins it's really hard to see. I will try to
describe it as best as I can. It is about four inches from the
bottom of the tank in the back panel.
<Mmm, I wish it were four inches from the top.>
With the glass being about 1 cm thick, the chip is about 2mm deep
and touches the side panel, but does not affect the side panel.
I'm not sure how thick the side panel is, but it honestly
seems like it is thinner than the front and back panels,
<Mmm, I hope not. The sides should be the same thickness as
the front and back>
so I don't know how close the chip is to the inside of the
tank. The inside of the tank doesn't seem to be affected, I
ran my fingers over the silicone seal and there are no cracks
anywhere. The tank was made in June 2002 and I'm not sure how
long ago it was up and running. Currently I have the tank sitting
on my front porch filled literally to the brim and almost
overflowing to test its water-tight integrity and there are no
leaks (7 hours later). I guess I just wanted your opinion on
whether or not you think this chip is something I should worry
about. I have read every one of the pages you have on chips and
cracks and I am leaning towards it being ok.
<I would likely go ahead and use this tank, however, I would
definitely "fill in" the chipped, missing area with
Silastic (any variety, color as it's outside the water) to
prevent cuts from hands/fingers should they be in this area...
You can "glom" it on, let it cure, and trim it later w/
a single edge razor blade>
Also, the plastic on top of the tank is cracked in quite a few
places and I was wondering if that is something I should be
worried about and if I should replace it, leave it alone, or
maybe fill them with silicone or something.
<I would fill these gaps with a medium-bodied acrylate
Thank you so much for your help and this great website!
<And you, BobF>
Small chip on 125 Gallon tank 12/31/10
I have a small chip on my 125 Gallon tank on the upper right hand
corner of the front glass where it intersects with the side
<I see this>
It does not appear to have ruptured any silicone. I do not think
that this will pose any structural risk (My LFS doesn't
either), however, I would like to have another opinion as well.
Pics are attached.
<I concur... the placement, size, shape of this chip should
pose no difficulty.>
Thanks in advance.
<Welcome! Bob Fenner>
Re: Small chip on 125 Gallon tank
Thanks for the prompt reply. Have a good new year.
<Thank you, and you. BobF>
Re: Small chip on 125 Gallon tank
One follow-up question. Is there any way that I can 'fill
up' this chip (For esthetic purposes),
<Mmm, not functionally, nor "very" aesthetically,
but filling it, screeding it level with some clear
Silicone/Silastic is often a good idea... to prevent cutting
one's hands, fingers>
or should I just leave it 'as is' and live with it
(The tank is full of water now so I cannot flip the tank
20 year old fish tank
You guys are really great! I couldn't find an answer on previous
posts, so I hope I'm not wasting your time with my question. I
recently bought from Craigslist a 150 gallon tank (72" long) which
was never used, but is 20 years old. The silicone does not seem to have
yellowed (I have some experience in fish tanks and handy work), and is
still soft to the touch.
Besides for that, I bought it to upgrade from my 75, but having no room
in my house for it, it's sitting on my back porch covered, but in
freezing temperatures (NJ) until I build a new stand for it. Do you
think it will be a problem? Do I need to replace the silicone?
<Mmm, I'd take a/the small risk of this tank having some issue
with the old/er Silastic/Silicone here. I know of many such sized glass
thanks of this and older age that are fine>
If I can one more question, it has a chip on the long glass (like a
rock hitting a windshield) less than 3mm wide, and a little more than a
finger nail deep. From reading previous questions the answers are
chipped corners, but couldn't seem to find one real similar to
mine. I filled the tank for about 24 hours to test it, but I don't
know for sure when the chip got there. Before or after the water
<I'd re-test, refill it to check>
I'm pretty sure before, and I just didn't notice it. Should I
<Not likely, no>
Thanks so much!! Your answers are real helpful, and sometimes
lifesavers (for the fish of course)!!!! Keep up the great work.
<Thank you for your positive comments, input. Bob Fenner>
Re: 20 year old fish tank `12/27/10
Thanks so much for the fast reply! Just to be clear on the first part,
the fact that the tank is outside in freezing weather (plus snow) is
not a problem? Thank you so much again for your time!! Eric
<Not a problem with the cold weather. Silicones, once
"cured" are fine to very gold temperatures. Think on their
"other" main application: Holding glass windows in place in
buildings... at times in very cold settings.
Cheers, Bob Fenner>
Cracks/chips/deformities in 75G tank
<Hi there> I recently bought a used "older" tank
off of Craigslist, I went to pick up the tank at the owners place
and didn't notice anything out of the ordinary (it was dark
though and I missed a few things, my bad for not getting a
light), though he did have it set up and I noted that the wood
stand and board he had it on showed no signs of even the
slightest water damage (just a few drops underneath the filter,
which is normal as far as I can tell from my tanks). Anyway, I
get it home a few days later, set up and test fill, holds just
fine, so I fill it 3/4 put in substrate, some guppies and let it
start cycling. 3 days later I noticed some "unique"
deformities on the tank and I'm attaching photos, the one
outlined in black is hard to see, but it looks like someone
simply pressed the glass in in that spot. Should I be concerned
with these? Any remedies? Preventative measures?
<From what (little) I can see, these blems don't look
"too dangerous". I would not be concerned>
Thanks -- Patrick
<Welcome. Bob Fenner>
Re: Cracks/chips/deformities in 75G tank...
Yeah, my camera kind of stinks, the indentation (black outline)
seems to be about 1/8 inch thick at most, while the yellow circle
w/line thing is about the size of a dime (the yellow is the
deformity itself, I simply filled the specific pattern in with
yellow to make it stand out), also, I noticed a slight bit of
bowing on the tank, I'd say about 1/8 of an inch as well on
the front and back, I've never had a glass tank of this size
before and was wondering if this is normal,
as a precaution I reduced the water level to 1/2 until I'm
certain all is well. Thanks.
Chip in front lower corner 20 Gallon tank, help sought
: Aquarium repair 9/7/2010
First of all, kudos to a WONDERFUL trove of incredibly helpful
<Glad you find it useful.>
Now on to my problem. I was transporting a used 20 gallon
17x17x16 tank and chipped the bottom corner.
<Hate it when that happens.>
Got home and filled it halfway. No leaks after 3 days.
<A good sign.>
I then filled a plastic trim molding piece I found at Home Depot
with silicone and pressed it on the
outside corner and waited 2 days then filled it. No leaks after a
day so far.
This is an AIO tank and I can't afford a new tank right
Could I take two long glass rectangle strips and silicone them to
the bottom of the tank along the two panes that the crack is
How about getting a piece of glass the size of the floor and
laying it on the floor and siliconing along the top of the new
glass floor? Do I have any other options short of replacing the
front pane which will be pretty expensive?
<Looking at the pictures, it appears to be a simple surface
chip which should not cause any problems. As long as the glass
pane isn't cracked, you should be fine. read here:
Thank you immensely for your help.
chipped tank, poor English, no search/reading
hi I am new here and really don't know if this is the right
place for this if its not please send me in the right direction.
thanks... well my question is I got a 72 gallon bowfront tank and
stand for 50 bucks but there is a small chip in the lower right
corner back glass I will post some pics to show you all and could
you please tell me what I should do! like is
it safe? or is the tank trash? any help would be greatly
appreciated thanks in advance.... the chip is about an inch long
and the pics look worse than it really is!!!!
<... Please send your note/s after running them through
spell-check... And read here:
and the linked files above. Can't see much in your pix... Bob
|here r some other pics!!!
the glass is still in and intact and nothing is wrong with the
Fix your English and re-send...
Re: chipped tank
here are some other pictures and the chipped glass is still intact
and the seal in not broken.
<... Mmm, a close/one-call... read where you were referred.
Advice on glass tank damage. 7/22/10
Hello WetWebMedia Crew,
Firstly excellent site, I've spent many hours reading your
advice. I have a question on a 48"x24"x24" (all
10mm glass including braces) tank which I recently acquired
second hand. It looks like in transport a corner has been
knocked and caused a piece to break in the front bottom left
corner, I've attached a picture to show the damage. The tank
is otherwise ideal. What would be the best way to repair this
kind of damage? Would adding a full
size bottom panel as a double base help with strength, or is
replacing the front panel going to be best?
<It looks like there is a pretty big crack in the front pane
in the silicone-seal area. This pane will have to be replaced in
order to keep the tank reliable. Adding a full size panel to the
bottom will not fix that issue.>
Also the tank is going on a metal stand, made from 40mm square
section with a center cross brace. Is a sheet of wood required
under the Styrofoam normally placed under a tank or should the
foam be directly on the metal?
<The metal rack will provide plenty of support. As long as the
Styrofoam is rigid enough not to deform and squeeze out from
between the rack and tank, no wood is necessary.>
Thank you for your time,
Can I fix my aquarium? Crack... Plexi for glass repairs...
I have read, read, and reread, the many posts on how to fix cracked
aquariums. Now I am just totally confused! Please tell me what you
It is a 125 gallon that has a u shaped crack on each end of the bottom.
I have no money to replace this tank and so must either fix it or
It is was originally fixed with a Plexiglas panel that measured 12 x 18
and which was sandwiched with silicone over each crack. The panels were
thin and not really done properly, I think.
<They are not. If this is an acrylic tank then silicone should have
never been used. If this is a glass tank (which I am assuming here)
then Plexi should have never been used. Silicone will not bond to
plastics in any sort of meaningful way.>
One of them came off very easily but the other took some work to get
I have removed the interior silicone and am now wondering what to do. I
don't need any more disasters as these past couple of years have
been pretty traumatic for me but I would so love to get this tank up
and going. Fish can be so wonderful and very therapeutic, and this tank
is my dream tank.
Although this aquarium is an oldie I feel it deserves a chance to be
fully functional again, sort of like me!
So, what do you suggest?
<If this is indeed a glass tank the only thing I would personally be
comfortable with is replacing the whole panel. A full panel patch may
work, but the bottom of a tank is nothing to take a chance on. If the
bottom panel is "boxed in", that is inside the side panes you
may well be able to break it out, cut out all silicone in the tank,
replace the panel and then reseal the entire interior of the tank. If
this tank was built with the sides sitting on the bottom you will need
to carefully dismantle the entire tank, remove all silicone and then
reassemble with a new bottom.
Either way it is a ton of work and a new bottom panel may not be cheap
(glass varies widely, call all you can for quotes). Knowing what many
will charge for such a panel you may very well be better off buying a
new tank used. This is the time of year to look, you may be surprised
at how cheap you can find one of these. I in fact have one that I just
want to get rid of! If you are anywhere near the center of California
do let me know!>
Thank you for the chance to ask.
Virginia Beach, Virginia
<Welcome, dang, nowhere near CA! Do look a bit for used tanks, local
classifieds or Craigslist. It will be less trouble and quite
cheaper for you. Scott V.>
<Bob, if you would not mind posting, I do actually have a 125 tank
stand and canopy free to a good home in Fresno, CA if anyone is
interested they can email me at
email@example.com><<Will do, have done. B>>
Re: can I fix my aquarium? 6/30/10
Dear WWM Crew,
<BobF this time>
Thanks for your info. Wish I was close enough to California to get that
tank. Thanks for offering.
Yes, my aquarium is made out of 1/2 inch glass and has been in use as a
turtle tank until fairly recently. It has one of those metal frames
that only goes along the bottom and the sides, but does not run across
the top as the old metal frame tanks did. The frame looks like it might
<Mmm, more likely steel/nickel... "chrome" finish>
I remember seeing these new, but it has been awhile.
One more question. Do you think that I could get it to safely hold
about 60 gallons of water and use it as a Riparium?
<Likely so. Do please read here:
and the linked files in the series above and those on Silicone
I know, I don't like to give up, do I?
If this could be managed via the glass sandwich method I would be very
happy but I do not want to be stupid about it, yet stupidity comes so
naturally to me!
<To all... excellence requires/takes focus, effort>
I will call around tomorrow to get some prices on glass. To be honest,
I am a little concerned about getting the frame off without doing any
damage to the tank or to me. I will see how the bottom fits in once the
sun is up.
I truly do appreciate your help. I started keeping fish when I was
about 7, in 1965, and learned early on to ask lots of questions and
listen hard to what was being said. I enjoy keeping biotype setups and
love all fish for different reasons but find myself being drawn to the
<Ahh, I as well>
Not overly cool, I guess, but I do love them and find them to be so
beautiful and silly at the same time. It seems that I have come full
circle as I started off with goldfish won during a ping pong ball toss
at a school fair.
I really do hope that my dream of a large tank doesn't stay just a
<Welcome Helen. BobF>
chipped fish tank, reading 3/23/10
Late fall I purchased a 150 gal tank. I found two notches/chips in the
glass in two of the back corners of the tank, can these be repaired or
<Maybe... depends on how bad the chips are, how much work you might
be willing to do to replace the pane, or adhere a piece of glass over
the bad area. Read here:
and the linked files above. Bob Fenner>
Cracked Tank Repair. 3/15/10
I need some advice/instructions on repairing a tank I was given.
Whilst cleaning and prepping the tank to be set up inside, I made the
rookie mistake of doing it alone and cracked one of the large panels
(1425mm x 440mm) from approximately 1 inch from the bottom of the panel
to the side,
to 7 inches at the top of the panel.
Whilst cleaning my house after recent renovations, I came across a
panel of glass in one of my cupboards. The panel of glass is 1375mm x
465mm x 4mm.
<Too thin to suit me for this repair>
This panel of glass is slightly shorter than the existing panel but
wider than the existing panel. I can get this cut to fit inside the
The idea I have is that I could cut the existing silicone out, clean
properly and silicone the new panel to the inside the tank to cover the
The question I need answered is, is this possible and if it is, how do
I attach the 2 pieces of glass together without getting any air bubbles
<Hard to do (and not necessary)... applying thin, closely-spaced
beads of Silastic, evenly placing a large amount of weight (I usually
use books) over the repair area glass (with the tank turned on its
Also what type of adhesive should I use?
Cheers Brock McInnes
<... read here: http://wetwebmedia.com/glstksilastic.htm
and the linked files above, particularly re cracks... Bob
Glass tank repair -- 3/6/10
I have an older glass aquarium that must have been hit recently with
something hard, because it has a new, smooth indented
chip in the front corner, with a single
crack extending from it about halfway into the side panel. It
doesn't leak, but I've emptied it and moved the fish to a bowl
just in case. Would you recommend repair or replacement? I do stained
glass, so I don't mind trying a repair. New tanks of the same size
(I think it's 20 or 30 gallons) are about $100. Thanks!
<Mmm, because of your glass experience... I'd likely try
Siliconing a strip (about 2 inches wide) across (lengthwise) the
chipped/cracked area, along the entire length... See WWM re. Bob
Broken 135 gallon glass Hagen aquarium
Hello Mr. Fenner,
I recently woke up to my 135 gallon aquarium pouring water onto
my basement floor.
I caught it with just about 4 inches of water left on the bottom.
When investigating the cause, I discovered a large crack in the
back glass running from top to bottom. The crack went all the way
through, separating the back panel into 2 sheets of glass. I
managed to save all the fish, and transfer them into a 40 gallon
until I get a new setup sorted out. My insurance company is
willing to pay for contents, but is refusing to cover the cost of
the tank, because they are claiming that the crack was due to
regular wear and tear on the tank. I would think that wear and
tear would be a valid excuse if the tank had failed along one of
the seams, but this doesn't appear to be the case. In your
opinion, does this kind of fracture occur as part of normal wear
and tear, or would you consider another factor at play here?
<Mmm, not what I consider "wear and tear", but am
surprised that the Ins. co. is covering anything here
The tank has been up and running for a year and a half, with no
issues at all. There were no leaks anywhere, just a sudden crack
and burst of water. I am an engineer by trade, and built the
stand myself, out of 2 x 4 's and 3/4 inch plywood coated in
fibreglass resin for waterproofing. The stand was anchored to the
foundation by 6 1/2 inch anchors along the length and 2 1/2 inch
anchors along the width. It sits in a corner in the cinder block
foundation of the basement. Everything was perfectly level, and
the tank was recessed into the wall, so there was nothing that
could have fallen on it, or impacted the glass to crack it. I had
a local aquarium store owner come in and take a look, and he
suggested that the cold air outside may have caused a shift in
the foundation, and the back of the tank to crack.
he thought the stand was more than sufficient to support the
weight of the tank and all of the contents. I have attached some
photos of the stand and dimensions to give you a better
understanding of the situation.
<Looks to be a very solid design. I do want to comment re the
stand construction... Is there a missing upright in the back
middle? This could be big trouble. All six of these uprights I
would make of 4 by 4 rather than 2 by 4" stock.>
Anything you could tell me would be appreciated, I highly value
your opinion. The red line shows where the tank fractured, and
the blue line in the 2nd picture shows where the base of the tank
sits on the stand.
<Mmm, well, considering the shape and placement of the crack,
it appears there was some sort of torsion and/or loss of level on
the right side of the stand/tank...>
Ps the insurance company would have covered it if I had put a
hammer through the front glass....
but not if it was due to a defect within the tank itself, or wear
and tear on the glass. (unfortunately it's too late for the
<It may be worth your while to contact the tank manufacturer
here. Bob Fenner>
Thank you in advance,
Windsor, Ontario Canada
Re: More: re: broken 135 gallon glass
Hagen aquarium -- 3/6/10
You are correct there is a support missing in the middle at the
back of the tank....I had it turned off when I saved the picture,
sorry. I'll replace all uprights with 4x4's and what are
your thoughts on placing a 3/4" Styrofoam sheet under the
tank to compensate for any irregular surface?
<Is a very good idea... And is posted a few times on WWM.