I use Harlan Diamond soft bedding for both my snakes and rats and I wont use anything else going forward. The reason I like this bedding is that it is very absorbant and keeps the smell down. My colony isnt as large as yours but the only down side is it's 17.99 for a 20lb bag and right now I go through about 1.75 bags per month housing 28 rats - 2 in each bin. Coldbloods.com is where I pick mine up from and Courtland is a great guy to deal with.