Generically speaking, its the amount of UVB intensity emitted from the lamp. 10% vs 5%.
Here is an excellent resource that thoroughly discusses this topic if you would like to dive into this further.
http://www.uvguide.co.uk/
Initial use right out of a sealed bag has always been fine for me. You will have to monitor it and add water when necessary.
You will see how it feels and will be able to tell when its "dry". You will want to monitor humidity.
I ran into this problem today too.
My normal supplier is Top Hat. They are a Michigan based cricket farm.
Top Hat Cricket Farm is out for at least another month as of today. I believe LLL uses them to ship crickets to the Midwest Region.
I had to order mine from Armstrong's after seeing...