Not done much with the tank. Was going to plumb it but other things going on.
Been using a sump pump to circulate water through this cobbled panel to warm the water in the tank a little. It works but not well. So I gutted it out for a rebuild.
I have limited space and wanted both hot air and water. So I'm trying to make a hybrid panel. I'm placing the Copper tubing between the cans to give it fin like effect. I know it won't be as good as form fitting fins. Do plan to use Copper wire to pull the tubing tight against the cans. Drill a hole under a tube through the plywood backing. Take a loop of Copper wire over the tubing and through the hole and a washer and use a screw driver or something to twist it tight.
With the tubing setting low in the groves getting a good air seal on the cans is going to be problem. Glad I did a pressure test. Had a couple leaks.