Understanding PPM

brownred · Oct 25, 2019

DWC grow:
Is it really this simple?
I have been told...
To know your PPM, you check your water before adding nutrients, say it’s 50 (hypothetical number).
Then you ad your nutrients, say it’s 500 (hypothetical number).
then you subtract 50 from 500= 450.

Is your actual PPM 450?

oldskol4evr · Oct 25, 2019

brownred said:
DWC grow:
Is it really this simple?
I have been told...
To know your PPM, you check your water before adding nutrients, say it’s 50 (hypothetical number).
Then you ad your nutrients, say it’s 500 (hypothetical number).
then you subtract 50 from 500= 450.

Is your actual PPM 450?

nope when you started with 50 and add 500 it 550 friend,the minerals are always there

brownred · Oct 25, 2019

I’m sorry, I meant subtract!

Aqua Man · Oct 25, 2019

So yes and no. Start with say 50ppm you don't know what that's made up of... At least most don't so add the 500 you end up with 500pm of ferts and 50 unknown (if tap the large majority will be calcium) but as @oldskol4evr said 550ppm.

But when posting it best to be clear you have 50ppm tap and 500ppm feed.

If your doing DWC there is quite a bit to it to be successful. It's easy if it's planned for and can be downright frustrating if not.

brownred · Oct 25, 2019

Aqua Man said:
So yes and no. Start with say 50ppm you don't know what that's made up of... At least most don't so add the 500 you end up with 500pm of ferts and 50 unknown (if tap the large majority will be calcium) but as @oldskol4evr said 550ppm.

But when posting it best to be clear you have 50ppm tap and 500ppm feed.

If your doing DWC there is quite a bit to it to be successful. It's easy if it's planned for and can be downright frustrating if not.

So in other words, after to mix your nutrients in, what ever the meter reads is what the PPM’s are.

nicolajanjak · Oct 25, 2019

brownred said:
I’m sorry, I meant subtract!

electroconductivity meters emit as small current in the solution to estimate the quantity of salt disolved in it .. more the water hold salts dissolved in it more it will conduct electricity.
(salt= hydroponic nutrients, microelements and others salts ..)

your tap water will probably be already conductive because of the calcar dissolved in it ( i have it in my state). its good because its calcium and magnesium.. but thats doesnt mean it already have nutrients (npk)
when you will add your liquid fertilizer it will show the total of salts dissolved, and thats the number you need to look

i would stay around 1.2 1.3 ms in dwc .. i think its the right numbers you can do much more but its detrimental. i dont use dwc but its pretty similar to dtw .. 1.2 ms probably enought for bloom

Aqua Man · Oct 25, 2019

brownred said:
So in other words, after to mix your nutrients in, what ever the meter reads is what the PPM’s are.

Yes but most only count the ppm of feed since it's know. Like I said it's best to post both.

Aqua Man · Oct 25, 2019

My RDWC system runs anywhere from 200 to 1100ppm total. That including the 120ppm from my tap depending on stage of growth.

brownred · Oct 25, 2019

Aqua Man said:
My RDWC system runs anywhere from 200 to 1100ppm total. That including the 120ppm from my tap depending on stage of growth.

PipeCarver · Dec 5, 2019

Aqua Man said:
My RDWC system runs anywhere from 200 to 1100ppm total. That including the 120ppm from my tap depending on stage of growth.

So I now have a ppm meter, What do I do with it? I get numbers like 120ppm house water then add nutes I get another number 900ppm I feed and test run off I get 1200ppm What do these numbers mean and what should I do with them?

Aqua Man · Dec 5, 2019

PipeCarver said:
So I now have a ppm meter, What do I do with it? I get numbers like 120ppm house water then add nutes I get another number 900ppm I feed and test run off I get 1200ppm What do these numbers mean and what should I do with them?

120 ppm tap is the 900 ppm is a fairly high feed I would guess bigger plants. Now the 1200ppm coming out would mean the soil ppm is higher than your feed ppm indicating a bit of a buildup of nutrients. Now I don't know soil so I'm not sure at what point you want to flush but in my limited knowledge of soil I would say it may be time to flush?

PipeCarver · Dec 5, 2019

Aqua Man said:
120 ppm tap is the 900 ppm is a fairly high feed I would guess bigger plants. Now the 1200ppm coming out would mean the soil ppm is higher than your feed ppm indicating a bit of a buildup of nutrients. Now I don't know soil so I'm not sure at what point you want to flush but in my limited knowledge of soil I would say it may be time to flush?

Yes its this Cherry Bomb at 5+ weeks of flower, I guess I'll have to water,water,feed,water,water till she's done. I started flower nutes too early according to your previous advice at 1st week. My following plants haven't been given flower nute's yet at 2 weeks of flower so I've learned something else here and 1200 ppm coming out might be the result of flower nute's too early? ....Yes?

Aqua Man · Dec 5, 2019

PipeCarver said:
Yes its this Cherry Bomb at 5+ weeks of flower, I guess I'll have to water,water,feed,water,water till she's done. I started flower nutes too early according to your previous advice at 1st week. My following plants haven't been given flower nute's yet at 2 weeks of flower so I've learned something else here and 1200 ppm coming out might be the result of flower nute's too early? ....Yes?

It's not the difference of flower or veg nutes... The ppm will be made up of different sources depending on nutrients used and uptake. I don't feel 1200ppm is outrageous by any means but it something to bring down closer to the end of harvest. This is where soil growers flush to being it down. In hydro we just change the res. It's not something I would look at until you get closer to like 2-3 weeks before harvest. But yes it will help you determine if you want say feed feed feed, feed feed water or feed water water etc. Just give you a snap shot of the soil. It's not a great source of info but it's info. Just don't put all your eggs in that basket is the way I see it.

PipeCarver · Dec 5, 2019

Aqua Man said:
It's not the difference of flower or veg nutes... The ppm will be made up of different sources depending on nutrients used and uptake. I don't feel 1200ppm is outrageous by any means but it something to bring down closer to the end of harvest. This is where soil growers flush to being it down. In hydro we just change the res. It's not something I would look at until you get closer to like 2-3 weeks before harvest. But yes it will help you determine if you want say feed feed feed, feed feed water or feed water water etc. Just give you a snap shot of the soil. It's not a great source of info but it's info. Just don't put all your eggs in that basket is the way I see it.

its just a new tool and I'd like to understand its numbers to better use it. I finally got its runoff ph up to 6 from 5.3 so its improving now with what I learned here, now to get a hold of the ppm I'll never have problems again and I'll be a pot growing wizard lol

Understanding PPM

Understanding PPM

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