I now use lucerne chaff and am cleaning my rats out only one third as often as I was before, and there is no ammonia build up. Everyone on the rat forum is swapping over to it and raving about it, including me. I'm even using it for kitty litter now!
Dust and ammonia build up are the enemy of rat respiratory systems. The chaff is superior at keeping these to a minimum.
Sugar cane mulch was OK, but just got gross with the rat pee build up. It really stinks compared to the lucerne chaff, over time.
Does it have to be lucerne chaff? My only reason for asking being the cost, as I am not sure if lucerne chaff is the most expensive out of all the chaffs or if all the types of chaffs are the same price?