I did not expect this BB to be in my first 3 (or 20), but the universe said I would wake up to a septic pro mixing water into the primary tank to empty it!
Ran outside, met the guy and learned a lot about our specific system, general principles and best practices, and some horror stories that reinforced my budding-yet-obsessive interest in humanure
(PS I'm working with the city and MN state regs to create a pilot: just my 'waste', a structure with multiple piles, water protection (above and below), wildlife and human protection (walls/fencing), carbon storage, and even an unmanaged control test pile. The idea is to have things tested to prove safe final product, and hopefully a clear timeframe for an unmanaged (abandoned) pile to be safe. Honestly I've already learned so much from this forum about 'poop beasts' that I'm almost tempted to scrap the experiment I had planned. What do you think?!)
Then I cut a sapling for my stick (that was too close to a structural foundation) (mightily in 6 hatchet swings! lol) and checked the secondary tank (a couple times in different places because the water was removing some material, making it hard to get a reading. I even added a rag per the pro's recommendation. He says they rarely do the stick test in this county and almost everyone roughly estimates the layers - which boggles me....). Luckily the system is working well and was in good shape, there was almost no sludge/scum in tanks 2 and 3!