I have a 75 gallon columnar tank with two small tiger oscars, a black ghost knife, and two amazon swords plants rooted in aquarium gravel substrate. I'm looking to get more plants, does anyone have suggestions for other plant species that are easy to grow? and is there something I can use as a substrate that will work better than aquarium gravel? something cheap hopefully. lol. any help appreciated. there is a T8 bulb on the tank and it seems to be working pretty well with the amazon swords in there right now.