We stayed at the apartment for a week with our two little kids. We had an excellent time. The apartment is very spacious and has three bedrooms. The main bedroom is very quiet. So if our kids were early birds, one of us could easily sleep in!
The apartment is very child friendly: crib, highchair, toys, sand toys, beach umbrella's were provided by Begona and Quique. The bedrooms have shutters, so the kids could sleep well and they did not wake up because of the light.
The beach is at walking distance. And of course Valencia is a great city.