125 gallon want to stock geophagus fish with black sand. Black sand expensive: on Amazon best deal: 45 lbs $60 1” = $180 / 1.5” $270 / 2” $360. Amazon.com : TheFrogHouse Black Aquarium Sand Substrate (45lbs) : Pet Supplies   I would need minimum 1.5" $270. Any suggestions for links to buy cheaper black aquarium sand (that sinks) for cheaper?