Given the usual 3 week fermentation/clean up time,it should compact more. you've got trub,cold break,& yeast down their. I had 1L of that on the bottom of the last batch I did in my Cooper's micro brew FV,& it compacted down to about 3/8" over the 3 weeks it was in primary.
Time & patience are virtues in home brewing.
Everything works if ya let it-Roady(meatloaf)