Slate bottom aquariums and "Leaker" tanks?

[rossmort]

Hi, I was at one of my LFS today and saw some interesting things. First off was a 29 gallon tank that was 12x24x24 that was drilled and had a slate bottom. Does anyone know what these would be used for? I was thinking that it could make a cool shell dweller tank since mine use 1/2 of my 20 tall height wise and could make use out of the added floor space. The tanks are only 20 dollars so it seems like I could make a hood and stand for it and have an interesting set up I am just confused about the slate bottom. Any info would be awesome!

Also, this place was selling some "Leaker" tanks as they called them. They obviously leaked, hence the name, but I was wondering if others had ever bought something like that and sealed them back up. What goes into that? Would I just be able to find the leak and add some extra silicone to the area or would I have to take it apart completely? A 46g bow for $99 sure would be nice if it wasn't a whole lot of work! Again, I am a newb in this type of thing so anything would be great. Thanks a lot everyone!

Ross

 

[madasafish]

Leaky tanks are best left to reptile and mammal enthusiasts who don't need large quantities of heavy water to keep their pets alive. Like my geology professor once said to me, "the earth doesn't forget faults." In other words, once a large rock has cracked, it has to be completely melted before that weakspot ceases to be weak. The same applies to tanks. Once a crack is made, it becomes the site for future problems. Anything short of melting the glass back down will only be temporary.

Some ppl do repair serious cracks, and have moderate success, but I think the best bet is always to go with the sure thing at first. Heck, it's not the tank that costs that much, anyway. An extra $25 or $50 for a top-notch, brand-new tank is a small price to pay for peace of mind.

As for the slate... I've never heard of this idea. Are you sure that the entire bottom was slate, or was the slate simply glued onto the tempered glass? Slate is not a particularly strong rock (though it is water-resistant). I'd be quite surprised if an LFS sold a slate-bottomed tank for fish. :? But it's possible!

 

[rossmort]

Just to clear up the leakers, they were not cracked, errrrrr well the ones that I was looking at a little bit were not. It seems like the silicone just wasn't good at spots. I would never buy a cracked tank but there was a sold sign on a 75g or so bow that was sold so I guess people do. A crack would never sit well with me, the bonding between the glass on the other hand, makes me think a lot.

The other tanks were all used, I was thinking maybe they were once for a breeder set up or something like that but they did say slate bottom. I didn't look under them but I don't see why anyone would glue slate to glass but again, I don't know everything! The more I think of these tanks the more I am wanting one for some strange reason! The weakness that you talk about doesn't sit well with me though although I wouldn't be moving this tank much I am guessing. Gez, With it being drilled it is causing all sorts of ideas and all of which will cause me to spend money on crazy ideas (DIY sumps and stuff like that).

 

[Fruitbat]

In the not too dim and distant past, the majority of aquariums had slate bottoms and metal frames. I've still got a few of these old gems stored away in my garage and one of these days I might get a wild hair and see if any of them will still hold water.

As for the 'leakers'....they can be repaired but the BEST way to do it is to completely take them apart (removing the silicone)....clean the glass thoroughly to remove any residue...and then glue them back together with silicone. Probably more trouble than it is worth, however, given the prices of aquariums these days.

 

[Menagerie]

There is an article on resealing a tank in the Articles section

 

[QTOFFER]

At the GCAS auction last month, someone was selling a vintage 20 long (circa 1970's). It had a slate bottom and a chrome frame. I spoke with the seller and was told that these tanks were originally sealed with tar! 8O

Trouble is, the tar seals would eventually develop leaks and there is no way to apply silicone to surfaces that were once covered with tar. The only way to make these leakproof is to replace all the glass sides and add a glass bottom on top of the slate. Then could silicone the edges. Seems like alot of work unless you are really into the retro look.

 

[rossmort]

WOW, tar eh? Do you know if that was something that was done on all slate bottom tanks? I have been falling in love with the shape because I know my shellie's would appreciate double the floor space, but I don't want to buy a time bomb or just something that will not be worth my time. Would any of you guys run a tank like this? They say they are guaranteed not to leak, but now you got me thinking "For how long!"

EDIT: ALSO--can they be supported the same as glass bottom (Just edges) or do they have to have a flat bottom?

 

[Fruitbat]

Actually the sealant wasn't 'tar'. It was a compound called 'asphaltum' which isn't exactly the same thing. There is a formula for this material in the ancient (1969) 'Innes' book. I'll check it out when I get home.

 

[QTOFFER]

Actually the sealant wasn't 'tar'. It was a compound called 'asphaltum' which isn't exactly the same thing. There is a formula for this material in the ancient (1969) 'Innes' book. I'll check it out when I get home.

When the seller said "tar" (his exact words), I was thinking to myself how unhealthy all those organic contaminants must have been for the fish. I would be interested to know what the sealant really consisted of.

 

[rossmort]

I just called the place that was selling the tanks and they did say that it was some sort of composite sealant. You know your stuff Fruitbat! For 15.90 a piece, hopefully I can bargain a little bit, do you think that it is worth buying? If I do I will need to build a stand and hood for it, I just want to make sure that my time will be spent on a worthwile cause.

 

[rossmort]

At the GCAS auction last month, someone was selling a vintage 20 long (circa 1970's).

Do you remember how much he sold the tank for?

 

[Fruitbat]

From Exotic Aquarium Fishes, 19th Edition, Revised by Dr. William T. Innes:

Aquarium cements, in addition to being water-resistant, should be firm, tacky and harmless to fishes. They should remain slightly elastic, so as to reduce the strain caused by the unequal action of temperature on glass and frame. A cement meeting these requirements, and now in use by leading manufacturers, has (italics MINE) a base of pure asphalt, usually put up in fine broken sizes under the trade name of Gilsonite. This is thoroughly heated and mixed 50-50 with heavy-bodied linseed oil, so that when only moderately warm it has the consistency of putty. If used in this condition it will be quite firm when chilled by contact with the aquarium, which will be ready for immediate use. A little whiting may be added if desired. It is rather difficult using this cement in tanks of over 10 gallon size. Doing the work where the air is hot prevents the cement from firming too quickly on contact with the frame.

Heavy linseed oil is difficult to purchase. It can be made by slowly boiling and stirring the ordinary raw kind until it is reduced about 25% in volume. This is an unpleasant 15-minute job, and should be done in the open if possible. The smoke is acrid, but the result is superior.

After setting glass, especially on a large aquarium, cut thin small wooden wedges to place permanently at intervals in the cement between the frame and the glass in order to insure the glass firm, even support.

Surfaces intended to bind permanently with cement should be cleaned before applying it. Traces of oil or fingerprints can be removed by rubbing with a bit of clean cloth dipped in any quick-drying solvent, such as alcohol.

Also from 'The Innes Book'

A durable, quick-drying cement suitable for use by the amateur is made by mixing red lead in half spar varnish and half raw linseed oil. This varnish is highly water-resistant and costs more than linseed oil, but in the small quantity used by the amateur it is a wise investment. If one objects to the rather brilliant orange-red of this cement, it can be toned down to brown by the addition of a little lamp black.

Amazing what people used to have to do before the introduction of silicone cements!!!!! 8O

 

[rossmort]

Well even though the tank is the perfect size for what I need upon closer inspection, the cement bonding the tanks were really dried out and I don't want to waste the money working on a tank that could be "dying"

Now, to try to find a tank that is a 2 foot cube and only 12" high

 

[madasafish]

Hehe. I guess that dates me, Fruitbat. Still wet behind the ears over here!

Ross, I mentioned the possibility that they would have glued the slate to the glass because I've seen similar things done before. Ppl often glue slate to glass or to another board and place that in the tank in order to give the bottom or back of the tank a rocky look. Prob. quite tough to clean in that case! Obviously, Fruitbat's hit it on the head, though.

 

[rossmort]

Yeah, it was definitly just slate on the bottom (Was able to look into the drilled hole). Cool little tanks though, my multi's would have been so happy