So...I had a little water problem recently so I still haven't added any more fish than the 2 white cloud minnows who currently reside.

Here are my water specs (10 gallon tank- all water changes on schedule)

9-22
NH3/NH4- 1.0 (I found out my wife had been feeding the fish w/o my knowledge cuz she thought they needed more..doh!)
NO2- 0
NO3- 0
PH- 7.4
KH- 2

9-29
NH3/NH4- .5 (much better and no dead fish, phew!)
NO2- 0
NO3- 0
PH- 7.2
KH- 3

I'm hoping the water test on Wednesday will show better nitrate/nitrite numbers so I can add more fish. (I believe the number should be around .3...?)

Here is my question:
I've decided to add a heater so I have more options of species. In the future I'd like to have live plants which means new fancy lights. When I decide to add lights and live plants how will this affect my water quality? Should I wait to add tropical species until both the heater and live plants have been in the tank for a bit?

Thanking,
Dawgthis