Hi guys, thanks for your words. as I already mentioned, i just use easygrowing plants, but sometimes they just dont wanna grow like I want. Two identical tanks can be totally different, one kind of plant grows like hell in ione tank, but in the other they die. But dont worra, try something else, not too many species in one tank, but a lot of specimen if yozu newly plant a tank. Put as much green in as you can, and when its full, add some more plants ;-) This changes the "climate" in the tank to plant-friendly. I've always had no problems with this "method". To the substrate, in some tanks I use brown fine (1 to two mm/diameter silica gravel from the German aquaristic supplier "dennerle" and in the other ones I use silica sand from "house building supplier shop" sorry dont know the english word for "Baumarkt". Big shops were u buy wall colour,concrete,wood,etc They selll 40kg sacks for less nthan ten Euros. In aquarium shops, u pay the same price per kilogramm for the same sand, just packed in smaller sacks. Ther is no difference between sand and gravel in the plant growing.