De-Nitrate

[BadRoma1]

go for the sand and don't doubt. it's not recomended to use crushed coral as your substrate if you want to keep more critters than just fish anyway. forgot to say that when i was doing my water changes it helped to drop nitrates a little, but only for that day. it also confermed an article where it was stated that u have to constantly flush your system with fresh water for it to make big difference in nitrate levels, so one has to dig down to the bottom of the problem in order to fix it. little did i know that they ment it literaly.

 

[Max]

I'd go for the sand to but, I'd use plain old sand . It will become live sand over a couple of months. You can buy cultures of the little critters over the net and it will save you a lot of $. Most live sand only has a few bacterial cultures in it anyway and very few critters. You can use any arogonite sand ," that isn't exposed to environmental toxins etc." that you can find in a salt water tank.
You can even use silica based sands with few issues. there might be a diatom bloom for a few weeks and it may not buffer your tank as well either. I even question the buffering ability of ca based sands after the initial introduction as the ph required for it to go into solution probably really can't happen very much in a tank.\
anyway hth