I second the Jacks.
3-2-1 formula
Part A is the Jack’s Hydroponics(5-12-26)
Part B is the Calcium Nitrate bag(15-0-0)
And any bag of Epsom salt works for the third part.
Per gallon mixture is
3.6g of Part A
2.4g of Part B
1.5g of Epsom salt
You have to mix them in order, a bucket of water and put in the part A and the Epsom salt and stir until completely dissolved. Once that’s completely dissolved you add in the Part B, and stir until dissolved…then ph to 6.0 in hydro or 6.5 in soil.
Same thing every time from seed to harvest.
This is by far the easiest nutrient brand/schedule I’ve used, and had the fewest deficiencies of any nutrient line up.