overall volume- ~155-160g
I do a 50g pwc
once a month. (my nitrates reached 60 about 2 months ago, but have since settled in between 20-40)
only reason I don't do bi-weekly is because its a fowlr
and I have 12 fish, all of which are juvenile, so my bio-load is relatively light for now.
I do have to stay on top of the algae but that's to be expected.
also in terms of what percentage you should aim for on your water changes, that varies widely depending on stock, bioload, skimmer efficiency, etc. you could start out at 10% weekly and see where your levels stabilize at. if they stay at 0-5 for trates, you could prob do 10% every ten days. id let the params be the judge of how often and how much you do.