Starting to dig the hole for the first part of my 3-tank sump. Originally I had intended to place them lengthwise, but I decided to put them perpendicular instead. They'll jut into the walkway that way, but it makes things more accessible under the grow beds, when I need to make adjustments to plumbing or get to the pump.
Our neighbor moseyed over to see what I was working on, and helpfully told me there's a lava flow under this strip that's filled with giant rocks that make digging impossible. Turned out I hit the septic field before I got to any big rocks, but it was deep enough to let me get the sump pretty much as low as I had planned. (Good thing I didn't go with my previous plan of burying an IBC to use as the sump!)