Not sure what you mean by "great water Parameters"?
This is a question we usually ask when a member says their parameters are 'good' or 'fine' or 'great' because we have no idea if they really are 'great' without numbers. And many stores say they are 'good' when they are not good.
To give you an idea, 'great' parameters (strictly speaking these are conditions not parameters) would be -
nitrate under 20 ppm, and as near zero as possible.
Other parameters depend on the fish in the tank.
Soft water fish - pH under 7.0, GH under 10 dH (180 ppm)
Hard water fish - pH at or above 7.0, GH over 10 dH (180 ppm) with some needing over 15 dH (270 ppm).
Your tetras are soft water fish and the platies are hard water fish.