The new enclosure is mostly finished now. As I have mentioned before, Duncan, my male grandis, had become very aggressive to Isabela, and the only option was to separate them immediately. Since there was some urgency involved, we had to build a tank that could be put into use in an early stage of construction. We have also taken the feedback on the other enclosure into consideration.
The new tank is made of spruce wood, MDF (medium-density fibre board) and triplex:

Here, too, safety first:


One side of the tank:

The result of one day of carpentry:

Every corner is marked and then the tank is taken apart. (It can't be transported to my house in one piece.)

The tank is covered with pond liner (not in the picture) and can contain 650 liters (172 gallons) of water. It is now inhabitable.
But we're not there yet. There is a lot more to be done.
This is going to be the land area:

To be continued.....