Tap water 50 ppm, scorpion Diablo and ffof, should I cal mag every water?

I always air on the side of caution with all nutes but this light seems to putting a serious cal mag demand or other issue tell me your thoughts!

-what ppfd/par/lux?
-what medium/watering frequency?
-how are you controlling temps and humidity and what are their values?

if the plant doesnt NEED the additional calcium or magnesium that isnt already provided by your food you're just pouring it down the drain.
if she's not showing any signs of a deficiency there's no need to , if you just want to for peace of mind do a half-strength dose once a week, but you're running the risk of causing a build-up for no reason at all. unless there IS a reason. then thanks the gods for the gift of cal-mag

In my grow 1g of mgnesium lasts about a week with 300w lamp