Planted Tank Guru
Join Date: Jul 2010
Location: Huntington Beach, CA, USA
Not me! I'm not a math expert but since it starts out as an estimate at best, you may have already over thunk it way back!
Since it all requires a balance between lights, plants, and CO2 as well as the ferts, there really is not going to be a precise correct answer.
Shoot for close and adjust as needed!