how long is live sand good for?

[keithbou30]

i took my ten gallon tank down about a week and a half and i still have alittle water in there but it has been sitting inside the whole time so you think that it is still good to put into my 72 gallon??

 

[jdieck]

Smell it. Chances are all bacteria is dead and decomposing so if you use it under those conditions you will start up a new cycle and significantly spike ammonia and hydrogen sulphide (rotten egg smell)which is a killer.