My tank water in my biggest tank keeps disappearing it doesnt happen in any of my other tanks just that one!
When i went away for a week the water was quite close to the top of the tank but when i got back i was shocked to see it was only half full where did it go. There's no leaks or anything and firstly i thought it was the heat from the lights but the lights had been off all week so not that! Or is it the weather all though my livingroom is the coolest part of the house so im confused.
Is it evaporation or have i got very thirsty fish,lol!

Please guys help me make sense of this before it drives me nuts

have u got a leak in there then have a look may have a leak

No i have no leak i keep looking and looking but cant see anything and no wet carpet.

is it an open style tank ? (ie tank without a lid but with a hanging light unit ?) what temps your water at compared to your room ? a big difference in temp of water to air makes a lot of evaporation.

If it is just a case of evaporation you could buy a condensation tray to keep the water in the tank.

My lid doesnt fit properly now im using an external filter the holes arent big enough, and when my other half tried fixing it for me he sliced the end of his thumb, so i told him not to bother...queezy even thinking about that incident!

My livingroom is the coolest room in the house but my temperature in my tank is 28C.

Where can i buy a condensation tray from?

Most lfs sell them I know pets at home stocks them cos thats where I got mine. Makes sense your getting evaporation if the lid doesnt fit well along with the temp of the air being a good few degrees lower than the water temp. I do think your best bet is a condensation tray, they are just a pain cos you have to move them at feeding time lol (lazy much ...me ...never )

Thank you i think il get my other half to take me to pets@home at the weekend so i can get one

That's a lot of water loss to evaporation! I keep two tanks open (one because the light makes it too warm, the other because it has an over tank luminaire). The one that loses the most loses about an inch to an inch and a half a week. Any more and I'd be extremely worried!

Even if a lid doesn't fit properly, it should stop the water escaping mostly. You can but try the condensation tray (beware, they get yucky really quickly). Draw a small black line, with a marker pen, on the glass of your aquarium and see how much you lose every day.

I agree it is a lot Time-Out but she says she doesnt have a leak, it'd be hard to miss a puddle that size on your living room altho rates of evaporation will differ depending on difference of water to air tamp and also the surface area of the water (evaporation would occur faster from a larger surface area). lol ok gonna be quiet now sounding like the science geek that I am

That's why I mentioned the loss I incurr to evaportation. That tank is the one in my album. It has a surface area of about 3750 squared cm. The other one, with the flaps I leave open, loses about half a cm every week.
We'll see after Nat gets a condensation try. They're only cheap, so it'll be an experiment

It hardly loses anything in winter tho, is that because the heat in my livingroom from the central heating is a similar heat to the heat in the tank? It will be an experiment but i just hope it helps.

my guess is that a large surface area coupled with a big difference in temp (air of living room being much cooler than the water) is whats making a big difference but yes a cool experiment to try out.

When you get the condensation tray put it in and next day just lift the lid to see how much water has gathered. should give you an idea of how much water you were loosing to the cooler air in the room.

Another factor could be humidity in your living room too, if the air in the room is quite dry (air conditioned or dehumidifyier in the house somewhere or just a well ventilated room ?) this would also increase the evaporation rate (insert geeky smiley with labcoat and goggles here)

Thank you but, you made me laugh when you said (insert geeky smiley with labcoat and goggles here)

Im glad someone can help me