Is it good to store a salt block with silica packs?
Depending on your climates humidity, if its too humid salt works like a big silica pack. It absorbs moisture, and you might get liquid salt runnoff. If you live in Denver Colorado, you could probably store it on your porch.

General suggestions are to wrap salt blocks in plastic wrapping.

Therefore if you double up that with an airtight container you can store it indefinitely.

Silica gel is also a form of porous sand that stores moisture and does not harm your salt block in any way. The two compounds are also separated by the silica gel packet wrapping.