That is a normal reading for a new tank started with live rock.
what has happened here is that you started with live rock which inevitably has some slight die off of bacteria or other biological material, as this die off occurs it turns into ammonia which then feeds the nitrosomonas bacteria still living in your live rock, this brings your ammonia reading to 0 ppm, which does not mean that no more ammonia is being produced, what it actually means is that as soon as the ammonia is being generated it is being consumed by bacteria and being turned into nitrite, the 0.05 ppm nitrite reading means that almost the same is true here, in this case you have a slightly lower population of nitrosbacter bacteria than is needed to immediately transform the nitrite into nitrate creating that small 0.05 ppm surplus of nitrite, as your tank finishes it's cycle your population of nitrobacter bacteria will grow to accomodate the ammount of nitrite being produced by the nitrosomonas bacteria and you will essentially have 0.0 ppm detectable nitrite and thus you will have a fully cycled tank ready for the slow introduction of inhabitants. Each time you add a new organism to the tank a small maybe even undetectable surplus of ammonia will inevitably occur that then turns into a small surplus of nitrite and finally is turned into natrate, which is why it is so important to stock your tank slowly.