Personally if you want to get into dialing in and monitoring PAR/PPFD id invest in a dedicated device. The one i use is about 60 bucks and works great. The photon app imo is not accurate at all. It might work for some but not a substitute for a real device.
Per youtube videos its very close to apogee meters which is good enough for me.
If you’re using an IPhone you’ll need a paper diffuser. I recently purchased a decent meter after using PPOTONE for 3 years and noticed a big difference in the readings. The App was reading about 200 PPFD lower than the actual PPfD from the light meter 
What meter did you get and how much. Been looking at them can’t decide if it’s worth it.
