Hello, I've been reading the getting started guide, http://www.thesaltybox.com/forum/help-and-advice/110278-setting-marine-tank-basics.html, ( for about the millionth time! ) and just have a few quesitons. This is probably impatience as i'm just starting a tank for the first time but i can't necessarily see an obvious answer so thought i'd ask. So, if my ammonia and nitrite levels are zero is there anything else to wait for before adding a clean up crew? I've read some things about waiting for algae so that there is something for the creatures to eat but if i'm honest i'm not entirely sure what it is i'm looking for. Assuming it is okay to add things, what would you recommend adding? Shrims? Crabs? Snails? Sooooo many choices! ( i LOVE Fire Shrimps ). Also read things suggesting that you should do a large water change after the tank has cycled.... is that before or after adding little critters? Thanks all! Andy.