To make sure that they get along, use skinks of a similar size and species. Enclosures can have several females, but males will tend to compete with one another. As a result it's best to give new skinks a trial run to see if they get along with the other skinks before moving them in permanently.
The difference is that a skylight filter is a basic colour correction filter with a slight magenta tint which has a similar effect on skies as a UV filter (which cuts out part of the spectrum), which is neutral coloured.
At one time no self-respecting photographer would leave a lens unprotected without a skylight filter, and if they didnât use a skylight filter then they would use a UV filter. But neither the 1A nor 1B guise is very popular nowadays, thanks to modern digital cameras.