i have heard argonite has its ups and downs,so, someone break it down for me. can you replace livesand with it or as an additive? what would some of the benefits be? does it pose a threat to anything in the tank? has anyone had any problems with it?

Angus,
You can't go wrong with aragonite as a gravel in your tank. Aragonite is a high calcium mineral from the oceans,has at least half amount of the natural trace elements just by itself. I'd recommend to anyone in SW "business". 1-2 lbs/ Gs of water. Do not overdose. Too much of Aragonite can be a result of way too high alkalinity and low levels of oxygen. Live sand is about the same when it's came from the right source. Live sand a bit lower in Calcium, but very good as a natural buffer. With a good water parameters Aragonite can least for a lifetime, while the sand has a 5-7 years "lifetime" It'll remain alive, but the buffering capacity will gets lower. Both, aragonite and live sand are the best substrates out there today, in my opinion. If you have a good estabilished live sand bad in youir tank right now, I would't bother to change it to aragonite.

what if i slowly added to what i got now?

im not sure bout this, but does arganite come in different colors? i saw a tank with black, and one that was red. anyone know bout that?