OK, Thank you all for your ideas !
It seems that my crazy idea gives you all a lot to think of !!!
And I had lot of fun reading through, specially when you came discussiong th idea of the skylight above the tank !!!
And knowing that our bedroom is on the second floor just above that tank, I would have to build a glass floor in the bedroom as well, but it will be nice at night to have a look on the stars at bedtime !
In the mean time, have completed my light setup, and planted my tank !
Photos will come soon. And we can discuss if my present setup could accommodate that no-light idea....
But I will continue my researches.
Anymore ideas are welcome, and may be one day I will remove these lights to achive my "water cube in the middle of the room" idea !!!
Lost in the desert...