Stone Technologies Corp Silicate Based Hardener Densifier Concrete Sealer X-2 (5 Gallon)

I purchased 15 gallons of the X-2 variety for my 5-year old driveway and sidewalks. Road salt picked up on Ohio roads had been dropped on the drive and already started pitting it where the car parks; thus I opted for X-2 over X-1. I applied the product with a 4-gal backpack sprayer ($30 at Harbor Freight) and was happy with that decision. I calculated approximately 267 ft^2 of coverage per gallon per application. This works out to about 135 ft^2 / gallon for the two recommended coats. It was cloudy and about 70°F most of the time I worked, which was ideal. The portion of the day it was sunny, the sealer evaporated so quickly that I had to put more on to get it to soak in; this took more product and took more time. I applied it at the end of September, and we're now in February. The sealed areas are a bit darker than the unsealed, but it is not unsightly (I ran out before I got to the patio). I credit the sprayer for being able to apply it more evenly than possible with a roller, though I can't say for sure. The sealed areas are obviously much more water repellent than the unsealed as well, so I rest easy that my concrete will see no more salt damage. But as the title says, time will tell! Update: 8/8/2017 After five years, the pitting we experienced before application has stopped. There has been no yellowing. Water does not bead up on the rough-textured driveway or sidewalks, so if that is your litmus test, keep looking. I'm satisfied though.