Just had a thought, it might be clearer to separate 'chambers' from 'level'. You will have 5 chambers according the pictures, but you'll only have three levels in the sump. The drain section will have one level that will overflow the sock holder baffle, then the sock, skimmer, fuge chambers will all be at same level before overflowing the adjustable return baffle. Then the return pump chamber will have it's own level (usually set by your ATO). .
Of course, I will see if I actually did get it when I do my test run

