Thank you Kathy, but I already started! I have added new substrate to half of the tank and plan on doing the other half in 3 or 4 days. The fish LOVE the new substrate as odd as that sounds! They all are hanging out on the "new" half. The other substrate is natural gravel and the new stuff is Black Echo Complete. I was planning on capping it with the natural gravel I scooped out of the tank, but everyone seems to like the "black" so much better that I think I will not cap it. I'll see what I think in the next week after the whole tank is covered in the black Echo Complete.