Hollatchaboy
Well-Known Member
I ran Lucas full strength with a couple different strains and never seen any problems. It was in a dwc bucket, in a 3x3, with a timber 4vs 400 watt led.
Questions about ppm in liquid fertilizer and final nutrient solution measurements
- Thread starter RookieMuffin
- Start date
rkymtnman
Well-Known Member
i'm confused by this. are you saying you were deficient in NPKCa and Mg (all 5 of the majors) by running Lucas at less than the 8:16 ratio??
nxsov180db
Well-Known Member
Yes I agree, that wasn't what I was previously talking about though.
RookieMuffin
Well-Known Member
Thanks for your input! Whenever I dilute Lucas I get deficient plants. So yeah even if it's high EC full Lucas is the way to go for me.
The plant didn't show deficiency signs of all 5 nutrients but even supplementing the deficiencies she showed didn't help my plants to bounce back to healthy plant. It worked for a short time and I had to use a lot of supplements. Now since I stopped diluting the lucas 8:16 ratio I don't need supplements anymore and they grow healthy. The reason is when diluting lucas to 50% strength for example there is not enough NPK Ca and Mg... Basically not enough of every nutrient possible. When using Lucas at 100% there is enough of all of these nutrients.
This discussion seems endless lol!
nxsov180db
Well-Known Member
The OP was asking why the calculated ppm of his nutrients was different from what he was able to read with a meter, I think that's where people are getting lost here. Calculated ppm meaning the real world ppm, not what you measure with any meter.
RookieMuffin
Well-Known Member
I think you are right. And that explains why my plants were deficient. When calculating the real world ppm I knew why. Every nutrient was too low. So calculating it helped me to determine the real world ppms without any meter measuring things that aren't even nutrients.
Hollatchaboy
Well-Known Member
What are you measuring that aren't nutirents?
You're talking about different things.
Elemental PPM has nothing to do with the PPM unit of meaure that is used when discussing total dissolved solids ("TDS").
TDS, when expressed in PPM, is a mathematical a conversion of the electrical conductivity of the solution being tested. When PPM is expressed using the 500 scale, the value indicates what value electrical conductivity would be if that the solution were sodium chloride; if the 700 scale is used, it indicates the electrical conductivity if the solution were based on potassium chloride.
"elemental PPM" indicates the PPM of the 17/18 chemicals that are used to make up a given fertilizer. If you look at the back of a pretty bottle of nutes, they will list the minimum guaranteed content of the fertilizer. Those percentages are used to calculate the elemental PPM's which is how nutrient mix ratios are expressed.
A given fertilizer may have an elemental PPM of, say, 600. When that fert is mixed, the TDS will be higher because PPM does not measure the number of parts per million. Per above, TDS is calculated based on how much current passes.
PPM is useful as an indicator of nutrient uptake but what's actually happening in a res is hard to nail down. The different chemicals in ferts are taken up at different rates (some in a few hours, some take days) and they impact EC differently.
Anyway, there is a vast difference between "elemental PPM", which is used to calculate the components of and the overall strength of a liquid, versus "PPM" as the unit of measure used to express a calculated value based on how much current can pass through that liquid.
RookieMuffin
Well-Known Member
I don't know. Because I don't know what the manufacteurer puts in the fertilizer besides the listed ingredients. Nute buffers aren't listed and so on. Theres a bunch of stuff that is not listed so I don't know what else my EC meter measures. But there has to be something else because when I calculate elemental PPM it's less than my meter measures. And my meter is working fine and calibrated so there has to be something else in the fertilizer besides the listed elements NPK and so on.
Like other peoples said there are other things in there which my EC meter measures. And when I calculate the elemental PPM I only calculate how much of each nutrient is in there. Thats it.
RookieMuffin
Well-Known Member
Thank you too for going into detail with it!
nxsov180db
Well-Known Member
Think of your meter as the weather man and your elemental ppm as the weather. Your meter can't possibly know the exact elemental ppm of your note solution, different elements have different rates of conductivity.
Right.
Unless you're pouring the chemicals from their container (Epsom salts is a good example), there has to be something other than the raw chemical that's used to make that chemical suited for use. I use Jacks 3-2-1 and they're granules for Part A and spheres for Part B. They're using something to bind those chemicals together. Those binders don't have an impact on elemental PPM but they do influence EC.
The bigger point about the difference between elemental PPM and EC — it does not matter. Elemental PPM indicates the PPM of the chemicals that are in the ferts while EC measures how much current passes through the liquid in the res. Those are very different things that will not be the same.
I've pasted the graphic from an Excel document I created to try to understand how chemicals are removed from a res. Some of this information is from the Bugbee paper "Nutrient Management in Recirculating Hydroponic Culture".
The reason I created this "model" is because I have a res that holds 28 gallons of nutes and I wanted (want) to understand how chemicals are taken up rather than blindly replacing all of those nutes simply because the earth has spun around 7 times. That's just silly. What this drove home for me (because I can be thick at times) is that, even though a res might have dropped from 810 to 400, there's still a shitton of chemicals for the plant to take up.
The elemental PPM's are 767.5 versus the PPM at 850/500 (I use PPM 500 rather than EC because it's more precise). Those are two different values and neither of them are measurements.
*it's always in the last place you look, isn't it?
nxsov180db
Well-Known Member
No they're not. They're just salts that are mixed together.
You're 100% correct.
I called Jack's tech support and asked. For most of the ferts that Jack's makes, they're mixed from the basic chemicals. Some of their ferts have small amounts of dye in them.
Mixing the dry chemicals is, according to the CSR I spoke with, pretty standard across the industry — dry chemicals are mixed together in the required proportions.
My assumption was based on Part B being spherical (called "prills", I just learned) which I thought would require a binder. According to Jacks, there's no binder - they're formed into that shape by the company that manufactures them.
Back to the main issue - unless there are fillers/binders, then the difference between the two is that PPM's for TDS are calculated from a measurement.
Last edited: