I use a quantum par meter it is already set up. I went by the settings in the manual as far as height range . I grow autos so my height and intensity will be different because I leave my light @ 18/6 the whole grow. You are going to switch to 12 /12 so you have to pack more light in in a 12 hour period vs 18. I looked in the playstore if you have android and found this app. you just set to full spectrum and when you do dli you put it on how many hours your light is on. just do measurements all over write them down and do an average per plant. below is a screen shot of app. the settings I told you about like full spectrum is for your leds not the mh (blue green spectrum) nor hps (yellow red spectrum) . Hope you figure this out. I don't know if you take notes but I know I can't remember everything so I journal my grows. I write down what I see in general and also note every feed . I write down everything problems ,etc. That way when a problem a rises you can look in your notes and try to figure out what went wrong. Notes are a must in my grows.