coral sand or aragonite?

is it better to buy coral sand or aragonite for the bottom of my tank??

 

I believe live sand is the best for the bottom of your tank. but some people choose to put coral sand in.

 

i personal did 1/2 coral sand and 1/2 agra alive live sand

 

The Aragonite will reach a point if going into solution at a higher PH of around 8.00 and will add in a little passive buffering to the system thats about the only reason I'd use it now if the tank is drilled and a reef ready then fill the corner overflows with as much as you want and then the overflows will reach a anaerobic , lower PH and acdic state in the bottom sections of the Aragonite sand pile and a very low PH speed up the dissolving , also will serve as a denitrater for you..

 

Aragonite is the best choice for both its buffering capabilities as well as its time releasing of trace elements into your pelagic area of your tank(water column) IMO!
I am not a firm believer in(common) sand> coral sand, I believe, is the same as crushed coral though...sand? are you talking about common sand like you would buy at the local Home Depot? That is no good IMO.

 

the fish shop told me it was crushed coral.

 

Thats also a good media it will add some mineral and dissolve a tad also but now as well as the Aragonite at the same given PH. I used C.C in a reactor we run many rectors use it as the CO's gas saturated water at a PH of 6.2 passes through it much easier and will dissolve it into solution. You will get some passive benefits from just the same ..