Parameters For Ei Planted Tank

Hi Gurus,

I am not so beginner in terms of aquarium experience but recently just plunges to have a planted tank set up for my discus.
I want to know what should be my paramaters in Nitrate, Phosphate, Potassium etc for me to have 2x a month of 50% water change.
I do not know if this is better for my discus sine they are used to have a every week WC.
Any comments or suggestions for 600liters aquarium?

Here are my parameters now:
No3 = 15ppm
Po4 = 1.5ppm
K = 20ppm
Fe = .1ppm
Mg:Ca = 2.1 (40ppm:80ppm)
3 econlux solar stinger 800mm

Thanks, bert