Post as many questions as you want! Like Saw said that is the point of a forum 
I know it's pretty much been answered but sand will be fine for your plec. White sand is fine, it just shows poo well like you mentioned.
If you're looking for cheap black sand I know here we have black diamond blasting sand..is there anything like that around you? I personally just use PetCo's black sand though.
I find sand a lot easier to clean than gravel. It looks more natural too IMO.
I know it's pretty much been answered but sand will be fine for your plec. White sand is fine, it just shows poo well like you mentioned.
If you're looking for cheap black sand I know here we have black diamond blasting sand..is there anything like that around you? I personally just use PetCo's black sand though.
I find sand a lot easier to clean than gravel. It looks more natural too IMO.