Ok well hank is right on the rocks. Use hydrogen peroxide to clean off unwanted algae, but you really don't want to kill ask the bacteria in the rock. As far as the sand, I would be weary of reusing it. Established sand can be hard to clean. You could always go bare bottom until you can afford new sand (you said this is temporarily staying at your house so I'm guessing you will be moving it again anyways). Not saying it can't be cleaned, but that would be my last resort. The tank can go without having to recycle it however I wouldn't attempt all of this at once. I would remove rock (leaving it all alone for now). Do away with sand. Clean the tank, drill it and install over flow. Keep all rock, fish, etc, in totes with powerheads, heater, and light (just as you would the aquarium). Put tank where it is going and fill up under the overflow (put new out cleaned sand in at this time). Add heater and water movement to tank. Plumb it all up. Once tank water matches tote water add the rock and livestock to tank. Don't let the water rise into the overflow or plumbing, let it dry at least 24hrs. Once it's dry finish filing it up and pray you did it right. LOL. (you could test it with tap water before adding anything, leaving all livestock in totes which would be recommended, but it seems like things are put in rush.) This week be an extremity busy couple days. Don't panic, try to stay calm and focused. I might have left something out or someone may add something to this.