Had a relaxed day today. Went and purchased some mini access chamber raising rings and a lid to use on the rainwater tank for access into it.
Then made a hole in the top of a aquacell module for a raising ring, attached it and removed the bottom of the module to make a hole right through. Made the same size hole right thorugh another module for the middle layer of the tank, then made a hole in just the top of a final module for the bottom of the access shaft. We will place a submersible pump here.