The crushed coral works well for my snails and shrimp I tryed many times to keep them in seasoned aquarium and no luck untill I added that. plants in the sump will be a Java fern and that's the only one for sure I know of I am still planning the rest of the plants display tank I have 2 African side neck turtles going in and still planning the rest of the tank the reason for the ro filter is in my area the water is horrible with the ro unit the water actual becomes usable so as a precaution I was researching what needs to be added gh and kh I was looking for 100 to 200 ppm that should cover most species