M. you don't need any other filter if you have 1-2#'s of LR
per gallon of tank water.
You should not run the skimmer because this will slow down the cycling of your tank.
Bio-balls compete for the same food as your LR
and will only slow down the growth of good bacteria on your LR
. It will also end up as a nitrate factory as bio-balls tend to require lots of maintenace. So as soon as you stop doing weekly cleaning of your bio-balls the nitrates will go skyhigh in no time at all. It is best not to use them. If you are using them remove them a little at a time to reduce the chance of over taxing your LR