Nutrients + Water Question

Another conflicting subject when searching for answers.
Does the tds of water used add to recommended nutrient mix? Example: If I wanted to mix a nutrient solution to 750ppm, do I count my water ppm's as part of that 750 or add it to the 750?
My tap water which is from a well reads 155ppm. I assume most of that is calcium and magnesium but I don't know for sure.
If its recommended to feed a fertilizer at 750ppm would I want to mix my solution to 905? To me it seems like I would. If not, the NPK and other nutes would be less right? I mean if my waters 155ppm is included then the solution would only be 595 with my water (mainly Ca and Mg) making up the rest. Hope that makes since. It's clear as mud to me.
I have looked online and find conflicting info. I even called some grow shops with the question and got conflicting answers. Hopefully someone that KNOWS can answer with the FACTS.
Thanks

seems pretty hard for a well. are you sure it's limited to cal / mag?

check toilet tank for red tinge. usually means iron and i believe it is no good for plants unless remedied.

i'm not an expert.

You want to go by total ppm... Never go above 900..

HydoDan said:

You want to go by total ppm... Never go above 900..

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So if Im told to feed my plants 900ppm of fertilizer 'X" and my water is already 155, by "never going above 900" I would only be giving 745 of fertilizer 'X'. The rest is my water. Im confused.

The ppm of your water counts so yes 745 + 155= 900

RottyRzr said:

Another conflicting subject when searching for answers.
Does the tds of water used add to recommended nutrient mix? Example: If I wanted to mix a nutrient solution to 750ppm, do I count my water ppm's as part of that 750 or add it to the 750?
My tap water which is from a well reads 155ppm. I assume most of that is calcium and magnesium but I don't know for sure.
If its recommended to feed a fertilizer at 750ppm would I want to mix my solution to 905? To me it seems like I would. If not, the NPK and other nutes would be less right? I mean if my waters 155ppm is included then the solution would only be 595 with my water (mainly Ca and Mg) making up the rest. Hope that makes since. It's clear as mud to me.
I have looked online and find conflicting info. I even called some grow shops with the question and got conflicting answers. Hopefully someone that KNOWS can answer with the FACTS.
Thanks

Click to expand...

You should get your water analyzed so you know what it is so you can make an informed decision about using it. Other than that all we are doing is speculating.