No skimmer, and no worries since I changed to ro/di.
I keep several kinds of macro, though, and my 'big 3' are always 0.
I change 5 gal (17%) once a week. I use a chinese food/soup container to scoop the water from the top (where it's dirtiest) and then scoop back in. Whole process takes maybe 15 minutes a week. 30 if you add in messing with the ro unit, and mixing up the salt.
