So, I'm still burning for hot water and I've got things figured out so far. It's going much better with the smaller pieces and a 3 degree differential.
I have a pool in the back yard. It's an in-ground 18'x36' and holds nearly 25,000 gallons. I developed a hole in the cover this winter, and didn't really know it. I went to pump off the water on the cover and unplugged it for the night. Well, it continued to siphon through the pump over night. Since I had a hole in the cover, it apparently drained my pool down nearly 2' of depth. So, for the last 2 nights, I've been running straight hot water from the "hot" side of my washing machine hookup to fill it back up. I figured this way, we can get in it sooner if I had 8,000 gallons of 110 degree water through my 20 plate.
I loaded the stove at 4:30 p.m. with 10-12 large pieces of healthy locust and turned the water on. That's really enough for me to get 12 hours during a day in the 30's. By 9:00 p.m., I had to add more wood! I think I've got another 4 or 5 hours of running the hose before it's filled enough to get the skimmers submerged. I'll let you know what temperature I end up in the pool. I'm hoping to crack 80 degrees, but we'll see.