If you didn't already, you can usually get a full water analysis from your local water co by calling and asking. The ones I get have much more info than what they send out to everyone. It usually shows all the elements - Ca, Mg, Mn, B, Cu, etc., and may show phosphate. Keep in mind that the reports are on one or just a few samples they collected. The parameters of the water delivered into your home could be different, depending - usually they're close enough for gov't work.
Looking at the detailed water report might help identify deficiencies in some of the more important nutrients / elements. Of course, one would need some idea of what the desireable range for level of, say Mn, should be in a planted tank to interpret the values listed on the report. "Accepted" values for macro nutrients like Ca would be easiers to come by.
Also, you might find it hard to keep algae under control if the tank gets much direct sunlight. Some people might have problems if a tank gets a lot of fairly strong indirect sunlight.