Every few weeks or so I see one of these threads, which is a good thing as too many people get sucked into the commercial hype/social media peer pressure that either proclaim you 'need' 5-6 types of filtration and/or promote the mind set that you aren't a 'real reefer' unless you've spent 10K+ on various types of expensive equipment
Little 12g AIO, 13 years, 10%/wk WC, just LR and LS (no mech or chem filtration):
* Once a month or so I temporarily attach a filter sock to the outlet during a cleaning session.
...and I ran a 55g high with a sump (just a heater in it) for 9 - 1/2 years with the same 'only LR/LS' setup.