[NaH2O]

I thought this would be a good topic of discussion. There are many factors involved with why we want our parameters within certain ranges. Keeping invertebrates means many of us want our Specific Gravity higher on the scale. Keeping stoney corals means we're interested in our calcium levels. I think that most of us keep our Ammonia and Nitrites at 0, or else we wouldn't have any inhabitants to observe. Many strive to attain 0 Nitrates, as well. I'm also interested in:

What do you test for? How often?

What are the ranges of parameters you strive for? *this is ultimately what I'm after, but didn't feel right without including the other questions

Why do you feel you need your parameters within these ranges? (i.e. what are your inhabitants, what had you heard or learned through experience) I feel this is important so we can learn how to better care for our inhabitants, by understanding their environment