I've recently aquired an aquaruim and I am looking to keep marine fish in it. But one of the bottom edges appears to have quite a number of chips in and i am comncerned about whether it will be ok to use as it is or if I will need to make some repairs first. It is quite an old tank, I'm not sure what the volume of water that it holds is, i think between 300 and 400 litres. The dimensions are 4' x 1'5" x 1'10". It has been in use for at least the past year before i aquired it holding 4 or 5 red belly pirhana and to the best of my knowledge there were no leaks or anything during this time. If anyone can offer me any advice it would be greatly appreciated. If any further info is needed please just let me know.

Many thanks in advance

Silicone can get dry rot, if the tank has sat empty for a long time after having been filled with water, the silicone seals may be weaker. So keep that in mind.
Fill the tank with water somewhere you wouldn't mind it bursting before filling it in your home or office etc. Also, when testing it out as well as when its setup on its stand, make sure its on a level flooring, for example lay some sheets of styrofoam to disperse the weight and pressure. This way there are not just a few pressure points touching the stand or floor.
Your tank is about 78 gallons (or about 294 liters), by the way.

Also if the chips extend into the seal or if they are on the outer edge of the glass will mean two different things. If its just spalled away some of the edge, that's not so bad.

Also, what type of bracing does the top of the tank have? Does it have strips that go across to tether the front and back panes?
And what type of frame does the tank have? Those are other things to look into. Cheers

Also does this tank intend to be a FOWLR or Reef. If the guy had Pirhana in it I would be very cautious of using it for a Reef tank because he most likely at sometime used copper in the tank. I would take out all the silicone and redo it, that way your certain you will have no Copper leaching.

Chips are usually OK as long as there are no cracks. Look for tiny cracks which may get bigger under pressure. If it is the tank base then get a piece of glass cut that fits snugly on the bottom of the aquarium (wet side) and silicone (aquarium grade) that in. Like it says on a previous post, fill the tank up to the top in a place where it is safe if it breaks.

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Koda Artificial Rockwork

I have a similar issue that I am concerned about....*sigh*