Leaking Tank

Hi,

The first thing to check is that the water isn't leaking out from under your tank's lid. I had a tank that did just that.

Are you as messy as me and get water everywhere during a water change? If some gets under the tank it could then seep out over a few days.

I'm not sure how you could check the tank's seams. For the side seams, maybe make sure they're completely dry then fix a paper towel/tissue over them for a few hours. The bottom seams would be trickier though. Is the tank flat bottomed or does it have a floating base? (is the whole of the bottom in contact with the table or is there a rim under the tank). You could use paper towels round the bottom if it's a flat bottomed tank but that wouldn't work for a floating base. The only thing I can suggest there is that you'd have to empty the tank, take it outside (when it stops raining!), run a couple of inches of water in and see what happens. But that's not something that you want to do till you've eliminated everything else.

My 25 litre tanks are flat bottomed, and I do get water between the tank and base mat (and between the base mat and work top) every time I do a water change 

Being flat bottomed, it should be easier to check for a leak in the sealant round the base. If you can get it as dry as possible, then pack round the bottom with paper towels/tissues, they'd only get wet if there was more water either seeping out from a spillage or from a leak. It would stop seeping from a spillage eventually, but a leak would carry on.

I'm not 100% sure, but if it does turn out to be a leak, a sealant leak would get worse before imploding. It's a crack in the glass that would go very suddenly. Obviously, you can see the sides and check for damage to the glass. Would it be possible to expose the bottom pane in sections to check for a crack?

With the tank being flat bottomed, do you have anything between it and the table? If the tank just sits on the table with nothing between, there is a potential for the bottom to crack. Any imperfection in the table or glass, or even a grain of sand caught between them can cause the bottom to crack. My betta's tank and the quarantine tank both have foam basemats under them, and before I bought them they had polystyrene tiles under them (they started to deteriorate which is why I got the foam)

Hi Liberty, based on my experience of a tank cracking, I would be surprised if yours had cracked. Mine cracked across the bottom and it was very sudden. The water poured out from between the tank and the cabinet and I could visibly see the water level dropping.

The only difference is that my tank had a floating bottom. But I would still be surprised if a slow leak was due to a crack. By slow, I mean more than one day. Although my tank had some additional help from me to remove the water, it emptied in less than an hour - and it is a 240l tank, so twice the size of yours.

How old is your tank? Although the seals on tanks are pretty impressive, I think they can eventually degrade over time. Though, I think this is more like decades. There are a few things that could speed up that degradation, for example if you've ever really cleaned the tank out with aggressive cleaning products (perhaps if you bought the tank second hand). I think I have also read that using some of the algae scrapers too close to the seals can eventually wear them away. But again I think this would take many years of use.

By the way, my tank cracked within days of completely filling it for the first time, with the heater on. I only had substrate and plants in it - no fish.

I hope you find the problem.

Great news Liberty  And thanks for letting us know!

Its a worry when something like that happens and you dont know the cause - the worse case scenario always goes through your mind and you pray like mad that its something simple