‘Substrate’ refers to the litter material e.g. clay or wood. Each type has its pluses and minuses. Personally, when my cat was using a litter tray, I used wood substrate. I found it good at odour suppression and it is relatively good for the environment. But, of course, I leave it to each cat owner to make their own decision. There is a greater emphasis nowadays compared to say 20 years ago to protect the environment so that aspect of the comparison is of greater importance. If the expense is not a major issue perhaps the deciding factor would be environmental impact. Read about Tidy Cats Lightweight Cat Litter – dusty.
