Love the river tank!
yep, my loach tank is set up with 80 lbs of rock, a very large filter and a bubble wall set on high. I have Black kuhlI Loaches, Striped KuhlI Loaches yoyo Loaches and Hill stream loaches. It's called the "Loach Motel"
Mine isn't set up just like the river tank but my loaches like it.
The heater is set at 75F. That's at the top of the hillstreams tolerance and at the bottom of the kuhlis. The heater very rarely comes on, it's just in there to keep the temps stable.
when the Hillstreams were in the unheated tank it was was staying at 75F.
All seem to be doing well.
Got the rock at one of those places that sells rock to house builders. He will sell it for twenty to twenty-five cents a pound if you don't want it by the huge basket. even let us pick out what we wanted.