Evaporated

I assume that you live in a very dry climate or in a mountainous region where water will evaporate rather quickly though 3 1/2 inches is a little extreme. Are you sure that it is not in centimeters?
 
for a 30 gallon tank 3.5 inches is something like 4 gallons isn't it? I'm trying to remember how many inches of water one of my water change buckets fills ;) anyway, that seems liek a heck of a lot of water even for wintery dryness evaporation. If everything is dry under the tank then it has to be evaporating somehow. have you checked to make sure the water isn't a lot hotter than you think? maybe your thermometer isn't working properly or something.... just a thought though. ;) good luck!
 
no... thats not 4 gallons... check for water again.. just to be shure, if you have a draft that blows across the tank, or if the house is REALLY dry, and if your water temp is high, all these factors could equal large amounts of water loss, cats will drink too, and maybe your water was lower than you thought when you filled it up or your filter wasnt on when you filled up and later you turned it on???
 
What's the humidity in your house? I keep mine at 50% and still lose about 1 inch of water in my 37g tank per week. The same is true with the 55g. My tall 20g has a tight fitting all-glass top and weekly evaporation is about 1/4-inch ...almost nothing. (plants grow well in this tank) 3.5 inches over night is uncanny though, but if your in-house humidity is below 20% (very unlikely) & you have a bio-wheel and other aerators, it could evaporate at an alarming rate.
 
Does it do this all the time? Maybe someone in your house removed some of the water?
 
Of course i don't know what footprint your 30G is - and i also dont mean to repeat what has been said BUT:

3.5 inches in a ~30G with
36x18 base = ~10G
36x12 base = ~6.5G
30x12 base = ~5.5G

of evaporated water. I dont see how that can be possible within one day even in the dryest of circumstances.
 
no, this was the first time that it has ever done this. today i had to pull up ome carpet by the fish tank because it was soaked all the way through to to the wood. it went throught the foam and everything....i think that maybe the water was coming from the filter. i dont have any inside cats or dogs and i am the only one who touches the thing. i dont live in the montains in CA. ...right now i have to go and try to remove some of the water with a "shop vac"
 
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