Over winter the project was suspended. But now in spring, I continued the work on the rack. Like I wrote before, the pallet solution didn't really satisfy me. Now my idea was a much lighter, but stable rack, which was made of (guess what) metal ;)
Like always, I mainly used spare parts, lying around. I used four stands, which I screwed to the tank using simple but solid brackets. They had an original length of 80cm. So to stabilize them over the length I fixed four cross bracings roughly in the middle of the stands.
Finally, I mounted two small weels to the two stands at the back. This makes it possible to move the whole device with few effort. It had the additional effect to have a much better stand on uneven ground, as the gum compensates a few millimeters.
Before mounting the wheels, I already thought about using only three instead of four stands. So after mounting the wheels, I was glad that this was not necessary, and the gum solved this issue.