Started using this 5mL pump bottle of
Arcona The Solution Repair PM last month. This is an AHA serum for exfoliation, and thus recommended usage is at night only, and for 2-4 times a week and not for every night. Personally, I would recommend wearing a sunscreen of at least SPF50 during the day if you're using any retinoid, AHA, or BHA product at night.
This serum is slightly thicker than water but is not viscous by any means. That means it goes on pretty much like water and absorbs instantly. This serum is unscented, but does have a smell of sort, neither good or bad.