Very small cracks on the bottom. – 06/14/07
First off, Incredible site. I can't believe it took me so long to find it.
<Me neither!>
Now, my question is:
I've got a 75 gallon (48x18x21) aquarium the has two very small "cracks" in it. They are located in the center (width
wise) and about 3/4 to the right (length wise) The cracks themselves are only about a hair thick and about an inch long,
barely visible, unless you know about them. Also, there parallel to each other, about 3-4 inches apart.
<... trouble... are these "just" scratches? At any length, I would NOT fill this tank>
There located on the inside of the tank. By that I mean that when you feel the bottom of the tank you can feel them
(finger nail gets caught as well). they can't be felt on the outside of the tank, so I don't think it's serious.
<Uhh, no... do you know how most glass is cut? By making such cuts, applying pressure to a side...>
I'm
almost tempted to call them scratches. It's fairly thick glass, and the tank is new.
<Oh? Take it back>
If it helps, the hood fell into the aquarium when we were setting it up and made the cracks.
<Yikes!>
Just curious if this is cause for concern, and what I should do if it is.
Thank you in advance for you help.
Justin.
<Let's see... no pix... a vague description... A response many thousands of folks will see over years time? Mmm, no contest... take it down, back... or change into a vivarium or such. Bob Fenner>
 

Glass tank repair (repairing a crack on the glass panel) <Grinding a pit...>  - 05/26/07
Hi there,
<Hola!>
Germán from Mexico writing, I am amazed with the amount of valuable info posted here, I am very grateful for all I have been able to learn reading this site. Also I am still reading the CMA, lots of good info too.
This is not a question, but some information I thought might be helpful to other readers.
<I/we thank you>
I am setting up a 200 gal tank, 12mm glass, I made it myself. I was going to use overflow boxes but after reading your site I decided to have it drilled, well I had a glass shop come home to drill the tank, I asked for 2 2" holes at the side glass panel, unfortunately the round piece of glass that came out of the hole was shot against the front panel (when it comes apart of the glass panel, it starts to spin inside the drill, I should have taped the glass on the opposite side to prevent this),
<Yes>
and it shattered it, any way it was a small crack, less than one inch long, but as we know any small crack will continue to grow to the edge of the glass in no time.
<Yes!>
even when I looked across the side of the glass (through the 12mm section), I could see how deep the crack was, it was only 1mm deep. I looked over your site and all the internet looking for a way to repair this but only found suggestions to replace the glass panel, which I was not willing to do, I would rather throw away the tank and buy new glass panels and plastic frames than tearing it down and cleaning all the silicone.
After thinking about the situation 2 solutions came into my mind, one was to drill a 1" hole to remove the cracked section before it would grow, and then plug the hole with a bulk head and a cap, or glue from the inside a piece of glass to cover the hole, this would save the tank but did not like the idea of seeing the patch, the tank is a view through dividing the living room.
The other solution was to "grind" the glass to remove the crack, then polish the glass to remove the whitish color after grinding, it would only leave a concave section on the glass.
<Mmm, I hope this area is near/er the top/surface...>
I got my hands on the Dremel tool and a scrap piece of glass and started to practice this method, I first used a green grinding stone (Dremel 85422 Silicon Carbide Grinding Stone), this allows to remove glass to a concave form, however the grinded glass looks whitish, then I used a polishing disk for metal, (Dremel 425 Emery Impregnated Disc), it is a rubber disk with very very fine sand, this started to smell to burnt rubber pretty fast so I took a new disk and used it with water this time, took the hose and pointed the water stream right where the disk touches the glass, the result is that it polishes the glass to leave the concave form to look like a magnifying glass, I was very impressed with the result, then I was ready to work on the tank. As I stated before the crack on my glass was still less than 1mm deep so I decided to go directly with the polishing disk (did not need to remove that much glass), I removed the glass section where the crack was, now there is no "line" on the glass that  may continue to grow. I suggest to avoid getting a 90 degree angle on the section grinded, the shape of the grinding disk will leave that shape on the glass, so you have to practice first to grind to leave a round concave form as that of a magnifying glass, (I am not sure if I am getting myself explained).
<Entiendo. I understand>
Well, I saw on your FAQ people asking about scratches on their tanks, these can be very easily fixed with the polishing disk, takes less than 5 minutes to remove them. Hope this info can save others the pain of replacing a glass panel when they find a scratch or a surface crack.
Regards,
Germán
<Again, thank you for this valuable input. If such damage is shallow, only surface (not through both sides of a panel) AND such blem.s are near the surface (not the deeper part of a tank where the pressure is greater) such repairs are possible. Mucho gusto y nos vemos. Roberto Fenner>

Overflow Noise/Glass Scratches - 08/15/06
Hi,
<<Hello!>>
I have a 54G RR Corner tank with a 1" drain and a 3/4" return.
<<Sadly undersized throughputs...even on this volume of water>>
I bought the whole reef set up used, but I can't imagine how the previous owner tolerated the noise!
<<Mmm, indeed...you can't really put much water through a 1" drain before it becomes problematic>>
I installed a 1.25" Durso standpipe (1" did not work, now I follow directions, doh!).  I have a 1/8" drilled hole in the top of the T of the Durso.  It was fascinating to watch the relationship between the air hole size, the drain line position relative to the sump water level, and the gurgling and flushing effect.
<<Ah yes, you are finding out just how "fiddly" it can be.  I would like to suggest you try enlarging the hole just enough to push some airline tubing through and down in to the standpipe.  This will help with aspirating/releasing air from the drain line and often eases the gurgling sounds.  It will take some experimentation to determine the best length/diameter tubing to insert>>
As I slowly increased the air hole from a pinhole up to 1/8", I observed the step by step decrease in flushing effect amplitude.  
<<Yes...allowing that air I mentioned to escape more readily>>
It started at about a 3-inch oscillation, at 1/8, it was gone completely.  Adjusting the drain pipe position also impacted the flushing effect and required small changes in the air hole.  
<<Pretty much all comes down to eliminating the obstructions (air bubbles) to the water flow>>   
OK, on to my questions:  I have extensive bubbling/gurgling noise in the sump from the drain.
<<From air that is "carried" down the line by the water>>
I have read on WWM two things to try: A "T" or "Y" fitting on the drain line, and aspirating the drain line from the top with air line tubing.
<<Yes indeedy...though I prefer a 45- or 90-degree ell fitting on the end of the drain line>>
I am confused about the specifics of both of these.  For the T or Y fitting, how is it positioned?
<<Is of little consequence...just position to direct flow in the direction you desire>>
I am guessing that it goes at the bottom of the drain line, with one leg submerged and one leg above the sump water level?
<<Mmm, okay...I think I'm with you now.  The purpose of the fitting on the end of the drain line is to "slow" the rush of water a bit.  So...experiment with the position to determine which gives you best results.  Either way you position it, I find that having the end of the drain line completely submerged usually works best.  And do be aware, it is usually not practical to expect a 1" drain to flow more than about 300/350 gph without much hassle and noise, as you seem to be experiencing>>
For the aspiration tubing, is the tube supposed to have its own hole separate from the existing air line in the Durso T cap?
<<Refer to my earlier comments re>>
Or does it simply go down the same hole?
<<Yup!>>
It also seems to me that the bubble/gurgle would be reduced if I had the water break on some live rock rubble or other irregular surface.
<<Can give it a try>>
I think I have seen reference to using filter pad material.
<<A detritus trap>>  
Next question: Even though I only have about a 2-inch drop from the overflow wall to the top of the water behind it, it still makes an annoying, trickle noise that induces the need to visit the bathroom at night (tank is in the bedroom).
<<Hee!>>
I am thinking of installing some kind of stepladder down to the surface.  Or perhaps a piece of filter pad would also suffice.  How have you seen this done?
<<Raise the height of the standpipe to raise the surface of the water in the overflow...it only needs to "fall" a fraction of an inch or so>>   
Last, the tank is used, and has a good number of extremely fine scratches that are visible depending on angle and lighting.  I have read that you generally shy away from glass polishing/buffing, but that usually seemed to be because the emailer was asking about significant/deep scratches.  What do you think about using a commercial buffer on an orbital drill pad, and follow with a thorough cleaning?
<<I think you'll do one of two things...nothing at all...or make it worse.  Scratches in glass "can" be repaired/removed, but unless you really know what you're doing/have done this before, I recommend you refer to a professional for advice/consultation.  You may find it is easier/cheaper to replace the tank...or learn to ignore/accept the scratches>>
Jack
<<Regards, EricR>>

Foggy glass
I have a 135 RR Oceanic tank that I purchased used. It was previously used as a cichlid tank. The tank has been sitting in dry storage for almost 2 years. When I went to clean it, I noticed the (inside) front glass panel is foggy. I have tried hot water, vinegar and rubbing alcohol, but once the cleaning fluid dries the fogginess reappears. Is this normal? When I wet the glass it looks perfectly fine? I have never heard of glass getting old.
Would soaking help? Any clues?
< Two things could be going on. The glass could be scratched and there is not much you could do about this. If it is precipitated with  mineral deposits then wipe down the tank with a vinegar and or lemon juice to dissolve the minerals. This is pretty common for a used tank. Be sure to check the silicon for leaks.-Chuck>
Thanks, Ken

Algae in scratches on glass
Hello;
<Good evening>
I have scratches on the inside of the glass of my 55 gal reef tank.  I'm not sure whether I created these scratches by using a metal scraper blade to remove coralline algae, or by using an algae magnet (I hear both actions, if done improperly, can scratch the glass).
<Yes>
Green algae grows in these scratches easily, making the scratches quite visible ;-) and making the tank generally ugly.
Assuming there's no easy way to actually remove the scratches, what's the best way of removing the algae from them?  None of the algae removal items (pads etc.) I've bought from my LFS seem to work.
Thanks!
<Other than techniques to make nutrients scarce through chemical filtration and/or competition, there is little you can do here. Are both sides of the tank scratched? One side may be better to turn as the front... The above methods are detailed in various places on WetWebMedia.com under marine algae control.
Bob Fenner>

Aquarium Disaster Prevention - and a small bubble in the glass
Dear Sir / Madam,
Upfront - My question is  - how do I detect if an aquarium could crack or burst. Are there any notable things to look for?
Here are my details leading to this question (my apologies for lengthiness).
- Last night (new years eve) I heard a "slight bang" come from my 65 gallon aquarium (long).
After inspection everything seems ok. Except for a small crack in the plastic molding at front top
right corner. The molding is siliconed to the glass but the contact area of the silicon is about 1/2" up - away from the crack.
That crack may have been there all along - or it may be new. Yesterday I had worked on the aquarium,
replacing 1/2 tank of water as I do almost weekly.
Also - there's a small bubble inside the front glass pane I didn't notice before - its 1/2 way up and near the same side of the tank as the molding crack. Its about 1pinheads wide, crest shaped.
- The tank (Miracles Aquariums brand ) was bought with a pine stand - all sides are supported under the tank. We bought it new in late August. Its a freshwater, fully planted, lots of fish, co2 injection, some wood ,rocks and about 2 inches natural gravel across the bottom. The lighting canopy never did properly fit over the sides. the top molding does have a bar through its centre. I'm thinking the whole system is max 1200 lbs.
It sits in the living room corner -along a retaining wall in our 50 year old apartment, but not across the joists. We felt that it was better to have it along the retaining wall than across the joists in the center of the apartment - in our limited space.
- We've placed a piece of wood (pine) about 1/4" high and 3" back - as a shim underneath the front of the stand,
as we had noticed the floor slightly drops towards the centre of the room.
The floor also drops from left to right about 1/4" across the aquarium.
I'm thinking that slight shifting over a few months time could crack the molding at a pressure build up point.
But wouldn't the glass have cracked? Or can glass ever so slightly curve?
Could a bubble in the glass mean trouble?
Thank You in advance for your time and efforts.
Any help with this source of insomnia is be greatly appreciated.
< You have two things to be concerned about. One is cracks and the second is leaks. Planted tanks and reef tanks have pretty high lighting requirements. These high intensity lights generate lots of heat. As the lights are turned off and on the plastic molding expands and contracts accordingly. The plastic loses some of its elasticity over time and may not totally rebound and develop a crack. These cracks may develop leaks through condensation under the lip and should be resealed. Cracks at the top of the tank usually are not structural. The top of the tank has no pressure put on the joints. At the base of the tank a setting floor could case uneven settlement and put stress on one point of glass over another. That would case a crack and a leak. Bubbles are a structural weakness in the glass. I would recommend a better safe than sorry approach and check the tank and floor to see if they are level. If not then you may have to consult a structural engineer to see if you floor are capable of handling this long term strain on your floor joists.-Chuck>
R Ryan

Aquarium Glass Scratch Removal Idea/Experiment
Good Morning,
<Morrow to you>
I’ve searched the archives and was unsuccessful in finding a similar post. Internal scratches on glass aquariums seem to be an accepted annoyance, one I hope to change.
<Great>
As an old fiber optic technician I have several grades of optic lapping film (See http://www.psidragon.com/store/enter.html  for an example) left over from polishing fiber optic connectors in the “good ole days”. I use these successfully to remove scratches from my wristwatch crystals, hence the origins of this Email…
<Okay>
I want to conduct an experiment utilizing said lapping film in an attempt to remove scratches on the inside of my tank and thought it would be fun to have you “involved” via before, during and after photos which I’ll send as close to real time as possible. Sound interesting? If so, we can arrange a date and time that accommodates both our schedules.
<Okay... or perhaps simpler digital/digitized pix over the Net>
The only concern (possibly moot) that I have is that I’m not quite sure what the film I have is comprised of. I’m not overly concerned about the abrasive mineral itself but the glue holding it to the film backing. Any suggestions on testing the film?
<Simple bio-assay... but I would not remove the scratches with livestock, water present... but rinse all out once the removal job was done>
I was thinking of soaking it in saltwater and testing for phosphate, pH etc. to see if any changes occur.
<Could>
Hopefully this experiment will result in something a great many of us can benefit from.
Tim
DuBois, PA
<Thank you for your efforts... reporting. Bob Fenner> 

Glass Repair
<Hi Steve, MacL here with you today.> I was cruising your wonderful site looking for repair ideas for scratched glass and found none. <That's because glass scratches are pretty much permanent, especially if they are on the inside of the glass. Acrylic can be repaired.>
I am considering repairing my 150 with a razor blade and super glue gel. <I'm assuming you mean you would scrape out the silicon with a razor blade and them glue it back with superglue? My understanding is that this will not work over the long term. That if you can get a bond that eventually it will wear out.> Do you know of anyone that has tried that before? <I know one guy who tried and ended up going back to silicon.>
I purchased Calfo's book on Coral Prop and find it a great source but lacking on Fragging Techniques-I need pictures. <Steve, that book is amazing isn't it? There are a few pictures in there and I'm betting he will be updating soon as well. You might try www.fragexchange.com I know they are adding more and more fragging examples and after IMAC in June will have a lot of good examples.>   Can you suggest a good book?  <I don't know that there is a good book on fragging other than Anthony's book but I'm sure it will be covered shortly.>
Thanks.
Steve