nutrients Hydro Nutrients Measurements With Tap Water

[bhankins]

I've got a simple TDS meter and several sources point to me needing around 900-1300 PPM, but I assume that is with distilled water and my tap water is around 250. Does that mean I should aim for 1150-1550? I've run it for the last two weeks at 950 total seemingly with no major issues. Thanks. 

 

[PapaBill]

I'm not big into hydro, so take what I say with a grain of salt (and hopefully the experts will be on later).  However, I think you are looking at it backwards.  Every time I have seen measurements on the water, it refers to ppm of "stuff", and a point at which the plant's roots are unable to absorb the nutrients.  If your base water is 250ppm, then you can add nutrients up to a point where the plants thrive, but are under the cutoff point.  I would assume that if what you are reading is recommending 900-1300, that the cutoff point would be at or above 1300ppm.
 
So you would be able to add the hydro nutrients/fertilizers up to that point.

If you are at 950, it sounds like you have some nutes in it already, and can add more if needed.  If it drops, you can add more.  If it approaches the threshold, you might want to back off and bring it back down.

 

[Blister]

Your target ppm includes the tds in your water source. Think of it this way your plants can't differentiate from what's in the source water and what you added to it. All it sees is the total.

I'd suggest that you start lower for younger plants (500-700) then move up to a stronger solution when they get bigger.

I'd also suggest starting with reverse osmosis water until you get everything dialed in and are comfortable with hydro. I had a hell of a time when I started dabbling in hydro this past grow and had everything really turn around after I switched to bottled water.



Neil

 

[queequeg152]

plants can differentiate whats in water.

carbonate for example will not be uptaken by plants. carboanate also contributes to waters conductivity.

if you have access to a water quality report, i would suggest you look how much calcium is in your water and adjust your nutrient profile accordingly.

of coarse with bottled nutrients this may not be possible.

I'm not big into hydro, so take what I say with a grain of salt (and hopefully the experts will be on later).  However, I think you are looking at it backwards.  Every time I have seen measurements on the water, it refers to ppm of "stuff", and a point at which the plant's roots are unable to absorb the nutrients.  If your base water is 250ppm, then you can add nutrients up to a point where the plants thrive, but are under the cutoff point.  I would assume that if what you are reading is recommending 900-1300, that the cutoff point would be at or above 1300ppm.
 
So you would be able to add the hydro nutrients/fertilizers up to that point.

If you are at 950, it sounds like you have some nutes in it already, and can add more if needed.  If it drops, you can add more.  If it approaches the threshold, you might want to back off and bring it back down.

thats not correct.

ppm can refer to two things, calculated concentrations from fertilizer additions, OR electrical conductivity of the water.

electrical conductivity does not tell you alot about the water, only that there is conductive elements dissolved.
10 grams of table salt dissolved in water will yield a higher conductivity than that of 10 grams of calcium nitrate dissolved into a given unit of water.