1st month of flower, I run around 1500ppms and decrease
to around 1200-1300ppms until I stop nutes 1-2 weeks brfore harvest.

I agree with snoop on the 3-2-1...however I offer you an alternative...try Lucas method...16b-8m-0g values represent ml per gallon. top off with ph'd water until you have used 100% of the amount of water you started with, then change with fresh nutes...If you get past 10 days close to 2 weeks before replacing that much water, mix and add fresh nutes anyway.

good luck

lw