Couple Questions

[Jaws]

1. I'm using a giant rubbermaid tub that I found out back to hold some live rock from my tank for a little while. What can I use to properly clean the tub without contaminating the water?

2. Is there a special way to add snails to a tank or do you just dump them in?

3. What would you say is the best size pump to use for a Beckett 3 skimmer? Is a Mak 4 enough or would a larger pump do a better job?