Originally Posted by Luke2112
Starting a small tank , can I use sand out of my established 4ft tank that is not running and take some out and just put it in or do I have to wash it? If so can I wash in fresh water and then with salt ?
So you have a broken down 4ft tank with sand still in it? If you're going to cycle the new tank from scratch I'd say go ahead and use the old sand bed after washing it out. The biggest worry about using old sand is large ammonia spikes from dying organisms in the substrate, but if you're going to be cycling a tank than an ammonia spike doesn't matter.