Bcavalli;963923 wrote: When I upgraded my tank about 4 weeks ago from a 90 to a 120, I bought all new sand and kept my refuge and sump intact. I seeded (it probably wasn't necessary with a fuge) the new sand with about a cup if the old live sand. Using this process I didn't even go through a mini cycle which I expected nor did I lose anything. Ive read reusing sand can cause drastic side effects. Plus you can change sand color or type to your new preference or needs. IMHO