Need nutrient dosage reccomendations

I got 3 plants that are ready for Nutes. 2 of the 3 are exhibiting a small calcium defenciency and look a bit lacking in nitrogen. The 3rd plant is dark green and has no symptoms(different strains) so my question is should I feed the 3rd plant or wait. Also what dosage should I give the first two plants they are only 3 weeks old. I’m using grow big by fox farm and calmag+. EI don’t wanna burn them the bottle says general feeding 10-15ml I was thinking 5 mls and 2 mls of cal mag. To much to little?

It’s odd that a 3 week old plant would have calcium issues unless you’re using r/o or very “soft” water. What’s your grow media? As far as nutes, go 50% and adjust as necessary after a a week or so. Pics would help a lot!

For best results, avoid Fox Farms nutrients.