actually, i don't have any gravel at all. i have the big gemstone rocks. i'm slowly increasing the amount of them. when i had gravel in my big tank, everytime i used the vaccuum cleaner, i got huge huge amonia spikes and my fish would die. i decided i'm not going to use gravel at all. i was thinking of buying these large rock like things at the store, but the bag was $15 for a 3lb. no way did I want to spend that much on such a little bag. i haven't had any amonia problems, my tank isn't in direct sunlight, and my entire kitchen gets very little light at any time of day. i'll buy some plants later after i've dealt with this algae problem (and of course on a payday), but i'm going to avoid gravel
