How To Shut Down A Tank?

[KrystaK]

I have a 20 Gal tank that I've had running for a little over 6 months. I found it too hard to clean three tanks a week and so have condensed my stock to just two tanks. My question now is, how to I shut down a 20 gal tank??
I've taken down smaller tanks before, but this one is just too big, and I'll require help to move it. I want to put it in storage in case I ever want to set it up again and so I want to make sure I do it properly.
 
I don't know if I want to keep the substrate, as it's pretty dirty and I feel no amount of rinsing will ever really get it clean. And I don't want the tank to grow any type of mold or anything because I stored it with damp sand. 
Is there any way to dry it out, while it's in the tank??  I can't really take it outside and leave it as it's almost October and I live in Canada, so the nights can get subzero and I don't want frozen sand, as that doesn't help me in storing it. 
 
So really, if anyone has ever taken down a tank of this size in the hopes of using it later, could you give me a run down of how you prepared? i.e Tank draining, cleaning ect ect...

 

[techen]

20 gallon tank is quite small. Shouldn't have a issue with if. I'd just remove the sand and put it in a bucket. Am sure it will dry out over time then just dump the tank in the shed or whatever. Job done Thats it

 

[DrRob]

I have a 20 gallon and a 40 gallon in the shed. The substrate from the 20 gallon didn't fit in a bucket but it dried out (and rinsed quite well) in the bottom of one of those clear plastic storage boxes and I bagged it up in a heavy duty rubble bag (builder gave me that, no idea where you get them). The plastic storage box is now a good place to leave extra kit and has made a good spare tank at a push.

 

[KrystaK]

Maybe I'll have to buy a tote I have one that I've used as a storage tank before but its got other stuff in it now.
So what should I do, line the tote with as heavy a clear bag as I can find and then rinse it as thuroughly as I can and leave it to hopefully dry out side? I'm worried about if it freezes, as then it'll be pretty useless until it thaws