FYI, nitrites and nitrates are not toxic to SW fish at levels encountered in SW tanks:
http://reefkeeping.com/issues/2005-06/rhf/index.php
Waiting until nitrite gets to 0 is just an indicator of your biological filtration maturation, but really as long as you don't get any ammonia readings means that your biological filtration can handle the bioload of the fish currently in there.
http://reefkeeping.com/issues/2005-06/rhf/index.php
Waiting until nitrite gets to 0 is just an indicator of your biological filtration maturation, but really as long as you don't get any ammonia readings means that your biological filtration can handle the bioload of the fish currently in there.