Hi Jenny,
Your highrise greenhouse is great and being a little closer to the sun is no bad thing
I`ve posted a picture of the greenhouse during construction so you`ll have an idea what it may look like once i get it finished.

http://usera.imagecave.com/Geo/Green...greenhouse.jpg

As for the aquaponics, i have a little experiment going on with some chillies to test the theory out and so far its looking good but i`m running out of space rapidly.
All they have to grow in is fishwater and they have been in that since they germinated.
They were pretty tiny as you can see from the pics:
http://usera.imagecave.com/Geo/Green...ies10thfeb.jpg

The big picture was taken on 16th march and the tallest are about 13"
http://usera.imagecave.com/Geo/Green...uachillies.jpg

The droopy leaves are due to the cold night temperature i think, as they pick up in the day when it gets warmer.
This is my first attempt at growing chillies by any method so i`m not sure what they need but they seem to be doing fine so far

Geo