http/www.aquaessentials.co.uk/index.php?main_page=advanced_search_result&search_in_description=1&keyword=unipac+black+micro+gravel
ive got this in my 6ft tank its good stuff and really brings out the colours in my bottom feeders
Pets at home do a small black gravel in bags of around 8kg. We have it in our 60L Cherry shrimp tank and it really brings out their colour. Can remember exactly how much it is but it is good stuff.