Ive had my 29cube for about 2 years now, its awesome, i think i have between 25 and 30 pounds of rock in it, just make sure you set up the rocks away from your glass so that you are always able to clean it, Clean up crew is always helpfull, snails, hermits, crabs. if you have any questions along the way feel free to ask, im sure many people on here are super knowledgeable and will be able to answer your questions