Dehydration is a bonding step which prepares the natural nail surface with the end goal of better adhesion. It dissolves the oils in the nail allowing for a more desirable nail surface. 

When should you be using a Dehydrator? 
-Before gel polish
- Before UV/LED Gels
- Before Acrylics

Dehydrator would go on first and remove the oils, EXPERT Primer would be used second to help attach the enhancement to the nail.