Before applying a floor finish you must make sure the surface of the floor is sufficiently smooth, dry and absolutely clean. If you want to stain your floor (change its colour), you must apply a stain before the finish. However, you mentioned that you don’t want to darken the colour of your floor, so we assume you are happy with it and prefer to keep it the way it is.
Now for the serious part. The two most popular types of finish are penetrating oils and lacquers. Both have ups and downs but it is undeniable that the lacquers are by far more durable and hardwearing. However, having dogs and kids complicates the answer a bit.
You see, penetrating oils will provide less protection and eventually turn yellow with age. They will also be requiring maintenance more frequently. On the other hand, oils can be spot repaired much more often.
As already said, lacquers are more resilient but somewhat vulnerable to scratches. Having a dog, especially a big one with proportionally impressive claws, can damage them. You must trim the pet’s nails regularly to lessen the effect. Personally, we would recommend a water-based polyurethane lacquer in your case. Polyurethane varnishes are incredibly durable and the fact that they are a waterborne product will allow you to have the clear finish you want.
As far as product recommendations go, Bona is the company which invented water-based finishes in 1979. They remain leaders on the market even today. 'Bona Traffic HD' would be an excellent choice for your floor. We can also recommend 'Junckers HP Commercial', which strikes a fine balance between quality and price.
Now, how to proceed? Well, keep in mind that different floor finishing products may have certain oddities. When purchasing such a product, you must be sure exactly how and when to apply it. Always follow the manufacturer’s instructions. If you aren’t sure about something, go to the place where you purchased the finish and ask them. Better safe than sorry.
Applying a water-based polyurethane finish? We can give you a few tips. The product is easy to work with so you shouldn’t have much difficulty applying it. Never shake a can of polyurethane because it can create bubbles visible even upon application on the floor. Polyurethane finishes also emit fumes so your best work in a well-ventilated room. Use a brush or cloth and roller to apply the coats of finish and make sure to always follow the grain of the wood. Don’t forget you need multiple coats of finish. We usually put three or even four. The good thing is that a water-based polyurethane dries very fast so you won’t have to wait too long before applying the next coat or finally walking on the floor once it is all done. We hope this information was helpful to you.