Issue is, the tech can be researched multiple times, but each level may only be applied to a specific planet once.
Why not then just say: max 1 per planet
Also, are previous levels a prerequisite for subsequent levels? If so and it's not a general rule (stated elsewhere), you should mention that here.
Is the assumption that each planet has a different biosphere, thus requiring separate research? If so, then this tech would be an exception to a general rule and stating the "max 1 per planet" will help point this out.
If there is a different reason for needing it researched once per planet, that seems to be more an improvement than a tech. I don't know if it would break internal consistency but I would suggest seperating it so that a society researches it once to get the capacity and then pay to implement it on each planet.