PPM question

Hello all my question is, i am running an ebb and flow system at my house and i have pretty pure well water (50 ppm) well i was having some cal/mag issues so i bought calmag + i read on the internet that i should add the calmag to my resevoir until it reads 200 ppm well my point is my plants need to be at about 500 ppm so im not sure if i need to bring my water to 200 and THEN add 500ppm of nutes or do i need to only put 300 ppm of nutes to bring the total to 500, thank you in advance!

If I understand correctly, you are asking:
Does it matter which nutrients I add to the reservoir first?

I think your answer is no. It doesn't matter if you add calmag+ before or after your other nutes.

Although I dont know if calmag+ should account for over 2/5 of your nutrient regime.

Best thing to do is keep an eye on the PPM over a few days, checking at least every 24 hours. After 24 hours, your water will drop. If at this time your PPM's are lower than when you started, your plants are still hungry; they want a higher ppm. If your PPM's are higher then when you started, your plants didn't eat as much as you gave them; they want a lower PPM.

Can't help with the amount of calmag as i've never used it.

hmm now that you put it in perspective if i use that much cal mag (mix it to 200ppm) that would be 2/3 my nutes and that doesnt sound right i think ill bring my water up to 100 ppm with the cal mag ( i add calmag first because my well water might as well be RO water, with NO calcium or magnesium in it) then im going to add my nutes to 500 if they get a touch of burn the worst i can do is flush and try again

IF you are staying with the same strain for a few grows, you should keep a log.

Record stage (clone,vegetative,flowering,etc) height, and PPM they can tolerate.
Then you can tweak your feeding regimes based on previous records with the same strain.

This will make subsequent grows a lot easier.

Even if you burn them a couple times, it's no biggie. It'll show you your plants limits, and will benefit later grows

Ya im gonna stay with citrus kush she is a really strong grower i just gotta figure out her nutes! I'm doing my res change today they are about 8 inches tall maybe a littler taller im gonna bring them up to 1.0 ec today which is 500 ppm on my meter