Changing Substrate - help...

[Malibu]

I want to change the substrate in my tropical tank. I don't like the color or the sand, and it's not got the right feel to it, if you know what I mean. It's river-rock colored (multi browns, reds, black, beige). I just don't feel it compliments the vibrancy of the tropicals I have in there. I want to go with more of a black with a little white thrown in.

I know I can't just toss new substrate in. Can I cure the rock in a tub of water for like a month or two? Should I toss in an apple snail or anything? I would definitely add a plant or two to help start the bacteria. Does it need to be filtered even if I don't put a snail in? Should it be in the light, or in dark? I've only ever cycled tanks, not rocks separately...

I want to get this started in the next couple of weeks, so any feedback would be helpful.