mix up a batch how you normally would and measure after each part and note that down, with that you can replicate that same concentration on your next batch
and yeah if there are charts available for your line of nutrients thats a place to start, though if your already using them and have a decent level they you already know what works somewhat for you as a baseline
indeed it is… my taps usally in the 0.04ec “20ppm” and 7.2-7.6pH range, you have some alkaline water down there sir thats for sure
Ok. So there’s no “set standard”… use a bit of trial and error, nutrient specific. If it thrives at 400 ppm but burns at 500, keep it closer to 400
Someone told me once to bring the water ppm up to 160 using calmag on another forum and it burnt the shit out of my plants,now I don’t ouch the water ppm lol
This is a good subject and I would like to know more as well
Now, whats the difference between ec and ppm
exactly you pay attention to the plants then get to know what works for you
ec and ppm are just different ways of expressing the same thing
Ask your questions bud, I’m hoping this helps other clueless bastards like us lol… loving how its exploded already!
here ill break it down
whats being measured is microsiemens “μS”
say 1000 μS is measured
that = 1.0EC
or 500ppm on a 0.5 scaled ppm meter
or 700ppm on a 0.7 scaled ppm meter
all of them are the same measurement
Just helps to know what you have and it will tell you typically on the label or in the manual
Wait… so. Ppm is bullshit. EC is more of a constant standard?
I’m feeding using a one part flower salt but on occasion I’ll add cal mag or silica at 2 mils to a gal and lower the flower nute to stay at a max ppm .
Nice thing with a meter you can see as well as know what each chemical effects the mixture.
I striated reloading ammo, expecting "precision " only to find out its "precision plus a bit of meh close enough " lol i take it this us the same idea
its not bullshit just another way of saying the same thing, like saying 1inch or 2.54cm its the same
but technical side of it should be μS or mS
European vs North American measurements
There also is the 2 settings 500 and 700 scale on the meter I run the 500 scale
Metric vs Imperial 
I shouldn’t be a 6 pack deep while figuring this out. So forgive the potentially stupid questions but.
Ok. My meter says its calibrated to 342 ppm. Then what
Tap water 30 ppm
Weak nute solution… 260 ppm
its calibrated at 342ppm just cause thats one of the easy “calibration solutions” and thats where it come out at for that specific solution which i think its NaCl, you can ignore that though as its not like your measuring in the 10000ppm range and need to have accuracy up there and have your meter calibrated in that range.
but yeah if a 260ppm is a weak solution for you then thats your base point for a weak solution
ppm/ec meters just allow you to replicate certain values more consistently than say eyeballing or volume or weight at times
I think that just answered all my questions! There’s no set numbers. Its more situational to your specific nutrients/plants and their reactions…
It also works good to check your run off also.
What would i be looking for in my runoff?
higher value than going in means they arent consuming it all, lower value means they are consuming more than they are given.
example say i feed MC to my plants say at 1.6ec, if the run off is 1.5-1.7ec thats fine as its not far off the starting value assuming the plants are looking happy, if its 2.0 or greater that means i have some build up happening.