As one who used Flourite (the black, colour is irrelevant here) some years ago, take my advice...don't waste our money. These substrates are not good for substrate level fish, like cories, loaches, some cichlids. There are two issues, the sharpness and bacterial problems. And the plants do not seem to benefit much if at all. When I removed this substrate in my 70g tank and replaced it with inert sand, the plants grew just as well. And there were no fish issues.
Seachem even tell you to use liquid and tab fertilizers with this--which always seemed odd to me if it is supposed to be nutrient-rich for plants. I used it without, plants struggled; with the ferts, better but not more than with sand.
Don't waste your money. After two years mine was dumped in a hole in the back garden.
