Should maintain more like 1.009 constant. But yours is ok for what your keeping.
Skimmer is just another form of filtering, but it takes waste out of the water column before it has a chance to accumulate. Kinda helps the water quality out. A skimmer will only work on the higher levels of Salinity, so I'd say with the way your keeping your water, I'd skip it.
Last edited by Reefing Madness; 02-13-2013 at 08:43 AM.