Thanks for the compliments, eventually it will be a plant soup. The ikea light is about 6 years old, but they have so many kinds that it's pretty easy to customize a look.
Well, doing some internet math I calculated that if it was an entire sphere it would be 1.39 gal, so with the bottom and top not being in the water column, I estimate around .9 gal which is 2/3 of the entire sphere. I am pretty confident its just under a gallon, so I feel a little better about potential livestock. Maybe a female and male cherry would work here. The normal pH is 7.3 with a hardness of around 3. I will check specifics later.