My mom has mild breathing issues so no smell else I hear about it.

Wal-mart carried a compressed bale of pine that's roughly $5 for 3 or so pounds. This will take care of the tanks once wil minor leftover. I can get the bag of pine pellets for the same amount except I get 25 pounds. Something else I've noticed with pine, besides the ammonia build up, is that it's very, very dusty.