I am really unhappy with the gravel in our 75-gallon. Here’s a picture below, yeah it explains itself. Now I can’t pick out all the white gravel out of it and since I didn’t find any efficient way to make it better, I’ve decided to scrap it all together. Now I’m currently looking at this picture for inspiration. I want it to look like a mini-River. Keep in mind that I don’t have a whole load of plants so my aquarium wouldn’t look like the pictures below (some cheap fast-growing plant suggestions would be appreciated).I don’t really need the soil for nutrients although it is a plus, and I really don’t want to spend more money on gravel. So I’m planning on using some leftover pool filter sand and some potting soil we have for our garden. Is there anything I should know before going ahead with this? Do I need a cap over the dirt? Since I really don’t want one. Is there an alternate dark colored substrate I could use (that’s cheap)?