# PPM question



## md.apothecary (Dec 20, 2007)

Okay... people like to dial in their nutrients for hydro using PPMs...

My question is that my water PPM is approximately 250-275

When I add my nutes, do I subtract my initial water PPM from the PPM after I add the nutes? Or do I go by TOTAL PPM after adding the nute solution? I want to make sure I have enough nutrients in the 3 gallons as possible.

I added my GH flora and now have 656PPM in the water (not subtracting the 265 ppm the water was tested at)


Any help? Thanks!


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## Puffin Afatty (Dec 20, 2007)

I use reverse osmosis deionized (distilled) water, however when I used tap water, I'd ignore the initial ppm and add the 800ppm of nutes....
in your example above of tap at 265ppm, if you wanted to have a nute ppm of 800, your meter should read 1065...good luck, try the hardwater micro if ph is too unstable..


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## md.apothecary (Dec 21, 2007)

coolness... i was aiming for 300ppm nutrient solution for a mild "early growth" formula.. im a little over, but should be okay.


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## sweetnug (Dec 21, 2007)

Add the nutes to the water then ppm.  Why would you subtract them if they are reading on the meter??  Thats how you burn plants man.


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## Growdude (Dec 21, 2007)

sweetnug said:
			
		

> Add the nutes to the water then ppm. Why would you subtract them if they are reading on the meter?? Thats how you burn plants man.


 
I agree, but I also would look into the hard water nutes or get a RO unit
250-275 is pretty hard water.


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## Puffin Afatty (Dec 21, 2007)

I really like my rod filter, makes great beverages and ice cubes too...I think Snow White loves it too...


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## Puffin Afatty (Dec 21, 2007)

sweetnug said:
			
		

> Add the nutes to the water then ppm. Why would you subtract them if they are reading on the meter?? Thats how you burn plants man.


 
dude was saying his tap water reads 265ppm BEFORE he adds nutes...in  order to know how much he adds, he must subtract the 265ppm the water contained AFTER adding nutes and taking a reading...I am saying just ignore the initial ppm of your tap water, insofaras the nute reading...That said, distilled water is a better way to go...


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## Growdude (Dec 21, 2007)

I too think you should count the PPM of your water because it contains many things that the plants do use, like iron, Ca, Mg ect so you can over do it on those micro nutes.
Thats why they have the hard water formula's for nutes.


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## md.apothecary (Dec 22, 2007)

sweetnug said:
			
		

> Add the nutes to the water then ppm.  Why would you subtract them if they are reading on the meter??  Thats how you burn plants man.



My question was how I figure out the total PPM of nutrient solution after adding it to the water.

The answer was, to subtract the PPM of the water (before the nutrient solution was added) from the TOTAL ppm after adding nutes.

If I need 300 PPM of nutrient solution and my water before adding was 200ppm and after adding was reading 500ppm, I would have to subtract the 200ppm from the 500ppm to find out where my nutrient solution (ppms) was reading.


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## md.apothecary (Dec 22, 2007)

Growdude said:
			
		

> I too think you should count the PPM of your water because it contains many things that the plants do use, like iron, Ca, Mg ect so you can over do it on those micro nutes.
> Thats why they have the hard water formula's for nutes.



I have actually used the HARD water MICRO nute from General Hydro, but believe it or not, it created a horrible salt build up and deposits all around the tank. Without using it, there is maybe an 1/8th of what was there with the hard water micro nutes.


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## md.apothecary (Dec 24, 2007)

Okay... so 4 days later... my PPM is 876 in the reservoir.

When I started it was at like 656 PPM...

Does this mean I need to add more water to my reservoir? The plants are turning greener now than before, but the PPM level raised as the water has gone down some, do I need to just add water to get it back to normal levels? or is something else wrong?

Thanks!


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## umbra (Dec 24, 2007)

There is more to the question. Need to check ph as well as ppm. It could be just adding water is all, but could also be salt building as a change in ph would indicate.


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