Questions about ppm in liquid fertilizer and final nutrient solution measurements

[medidedicated]

I use medical syringes to measure the nute amount.

Yes that's true weighing powder is more accurate... I'm thinking about mixing my own nutrient powder... But first I will use up all my liquid nutes so they don't go to waste lol!

It was a questions because I was wondering why my plants were deficient. I did all what people say. They always recommended something like EC 1.0 but my plants got deficient so I calculated what's in my nutrient solution when I'm at 1.0 EC and what the label of my nutrients say. After calculating how much of each nutrient is in my nutrient reservoir I came to the conclusion that it's not enought at EC 1.0 and I need a minimum of 1.7 to reach a good NPK ppm (and the rest of the nutrients of course).

My plants were sick. And with low EC (1.0 for example) like people recommended they were still deficient.

EC 1.0 stats:
N 58
P 49
K 88
Mg 68
Ca 69

EC 1.7 stats:
N 96
P 82
K 147
Mg 114
Ca 115

Now with EC 1.7 they start to look better.

But the initial question was: Why I have calculated fewer ppms than my EC meter measures (I measure in EC but I've calculated in ppm)

I've calculated the nutrients ppm with the information on my fertilizer bottle and it says 750ppm for all nutrients.

But I've measured 1.7 EC. Why do I measure more EC than the actual nutrients in there?

I've calculated 750ppm and measured 1.7 EC. So convert both to the same I have calculated 1.5 EC but I'm measuring 1.7EC. Why? Meter is calibrated and working fine. I was wondering if there is something in the fertilizer thats changing the EC but is not mentioned on the label like ph buffers or something. I measure 0.2EC more than I've calculated based on what the fertilizer bottle says.

I used this chart and got great results which is 1.4 EC on light feed. I have not messed with my ec meter in months but from what I recalled it was on the low side of the estimate (1.4ec in this case) because distilled as you know, is pure.

At first I thought ok you got .5 EC just about from the 1:1:1 like ratio which is right. But to say you are getting 1.7 instead of 1.4 or 1.5 then that is weird unless it is because you are using a formula that is not as detailed as this feed chart posted.

For example, following a personalized feed chart now relies on that person answering directly why their EC is a certain way. Was it well tested like this manufacture? What water was used, distilled or filtered mineral water? I am learning right now how the chemistry is more complex than I thought.

Reactions happening at all times. But if you followed this chart by your manufacture, you would probably get the same EC range but they assume you know the EC is just a sign of strength. I add .5 ec from my tap and get 1.9 - 2.2EC and was fine even through flower.

Some ingredients I thought have higher EC than others too don’t they? calmg adds .8 EC for example. Lucas, isn’t that like just two of the 3 flora trio? Last time I looked I thought it was, might explain too.

PS if you have plant issues, just showing pics and info on what you’re doing to them goes a long way, others might point things out that you wouldn’t of otherwise known. Not sure how long you grew ( I haven’t all that long) but hydro, plants should be growing/uptaking aggressively.

 

[PJ Diaz]

The other variable is that the %'s listed on the bottle may not be accurate. The numbers that manufactures are required to list are the minimum guaranteed % by weight, but nothing prohibits them from putting more.

 

[OldMedUser]

The other variable is that the %'s listed on the bottle may not be accurate. The numbers that manufactures are required to list are the minimum guaranteed % by weight, but nothing prohibits them from putting more.

A friend used GH 3-part years ago and when he got new batch he fed the same but got really bad nute burn. He still had some of the older stuff left over so we did some testing and found the older stuff to be much lower than the new stuff which was higher than what was listed on the bottles. Kinda like a hot-shot that kills junkies.

There are also buffers added to nutes that will raise the ppm higher than the listed nutrient levels. That would explain why the EC/ppm readings are higher than what the calculated readings say it should be. As they don't list those you can't factor in their influence in the calculations.

 

[futurebanjo]

I've found EC of about 0.5-0.8 for 'teenage' plants, slowly raising up to about a peak of 2.0 in through late Veg to mid bloom, maybe 2.3 at the extreme, but then tapering that back down in late flower to about 1.3 - 1.5 works well, which is roughly inline with the guidence on my particular nutes...

Once you're above EC 2.3 you are getting seriously hot on the nutes (depending on the nutes you are using, there will be some variance, and certain plants will tollerate more than others).

https://www.shogunfertilisers.com/media/4qqbun3d/shogun_-_hydro_feedchart_new.pdf

 

[futurebanjo]

A friend used GH 3-part years ago and when he got new batch he fed the same but got really bad nute burn. He still had some of the older stuff left over so we did some testing and found the older stuff to be much lower than the new stuff which was higher than what was listed on the bottles. Kinda like a hot-shot that kills junkies.

Totally...you have to measure EC, rather than put X amount of nute in X amount of water and hoping for the best.

 

[OldMedUser]

I've found EC of about 0.5-0.8 for 'teenage' plants, slowly raising up to about a peak of 2.0 in through late Veg to mid bloom, maybe 2.3 at the extreme, but then tapering that back down in late flower to about 1.3 - 1.5 works well, which is roughly inline with the guidence on my particular nutes...

Once you're above EC 2.3 you are getting seriously hot on the nutes (depending on the nutes you are using, there will be some variance, and certain plants will tollerate more than others).

https://www.shogunfertilisers.com/media/4qqbun3d/shogun_-_hydro_feedchart_new.pdf

Another thing to keep in mind is the rh. With chronically low rh like we have up north here I was getting toxic salts buildup over time that would show up mid-flower with older fan leaves going all orange/brown all becoming all thick and crunchy. That would just keep getting worse until even the small bud leaves were fried. At low rh the plants are drinking lots more water and pulling up a lot more nutes than the plants can use so it gets stored in the leaves until the levels become toxic and the leaves burn all over their surface rather than starting at the edges and working inwards.

Like right now the rh in my little veg tent is 31% while the rh here in the mancave is only 17% and both can go lower than that. The way to manage that is either humidifiers, big PITA, or feed at lower levels so the plants can utilize all the nutes that they pull up with the water and not store extra.

 

[nxsov180db]

Elemental PPM will always be different than the electric conductivity conversion

 

[futurebanjo]

Another thing to keep in mind is the rh. With chronically low rh like we have up north here I was getting toxic salts buildup over time that would show up mid-flower with older fan leaves going all orange/brown all becoming all thick and crunchy. That would just keep getting worse until even the small bud leaves were fried. At low rh the plants are drinking lots more water and pulling up a lot more nutes than the plants can use so it gets stored in the leaves until the levels become toxic and the leaves burn all over their surface rather than starting at the edges and working inwards.

Like right now the rh in my little veg tent is 31% while the rh here in the mancave is only 17% and both can go lower than that. The way to manage that is either humidifiers, big PITA, or feed at lower levels so the plants can utilize all the nutes that they pull up with the water and not store extra.

Yeah, just goes to show it depends on your individual environmental circumstances, theres no 'one size fits all'.

I got some crispy fried smaller sun leafs late on, but I'm reasonably sure that was down to overcooking the nute concentration, possibly also I ran out of verticle height so the may have been some light burn thrown into the mix. My RH tended to bounce between about 40% to 75% depending on lights off/lights on.
That said, mine were still hoovering up the water at that point, but then the damage is already done.

 

[futurebanjo]

Elemental PPM will always be different than the electric conductivity conversion

Yeah That's an intersting question, I've always gone with EC for simplicity, as there are several ways of measuring PPM. I'm kinda on the fence as to whats best, but I'm just gonna stick with what I'm accustomed to for now!

 

[OldMedUser]

Elemental PPM will always be different than the electric conductivity conversion

In case you didn't know EC and PPM meters read the same thing, EC or TDS, but report it using different scales that can be translated so users of different probes can talk the same language.

Like if you're in the states driving 61mph and I'm up north driving 100kmh we are both going exactly the same speed but seeing different numbers on our speedometers. 1 km = 0.61 miles.

 

[nxsov180db]

Yeah That's an intersting question, I've always gone with EC for simplicity, as there are several ways of measuring PPM. I'm kinda on the fence as to whats best, but I'm just gonna stick with what I'm accustomed to for now!

EC is still accurate as an indicator of nutrient concentration so there’s really no need to pay attention to total elemental PPM for most growers.

 

[nxsov180db]

In case you didn't know EC and PPM meters read the same thing, EC or TDS, but report it using different scales that can be translated so users of different probes can talk the same language.

Like if you're in the states driving 61mph and I'm up north driving 100kmh we are both going exactly the same speed but seeing different numbers on our speedometers. 1 km = 0.61 miles.

View attachment 5264639

Yes, that’s why I said elemental ppm will always be different. Anything measured with a meter is going to be electrical conductivity or a conversion of such.

 

[OldMedUser]

EC is still accurate as an indicator of nutrient concentration so there’s really no need to pay attention to total elemental PPM for most growers.

It's the same thing just presented with different units. If anything ppm is a lot more accurate if each point really made a difference. It's like measuring with a tape measure, (EC), or micrometer, (PPM). I don't worry about my nute sol'ns being ± 50 ppm so an EC reading would be close enough for that. When I was in a lab testing water for heavy metals to PPB each tiny point matters.

Yes, that’s why I said elemental ppm will always be different. Anything measured with a meter is going to be electrical conductivity or a conversion of such.

EC and TDS/PPM meters read exactly the same thing, Electrical Conductivity.

 

[nxsov180db]

It's the same thing just presented with different units. If anything ppm is a lot more accurate if each point really made a difference. It's like measuring with a tape measure, (EC), or micrometer, (PPM). I don't worry about my nute sol'ns being ± 50 ppm so an EC reading would be close enough for that. When I was in a lab testing water for heavy metals to PPB each tiny point matters.



EC and TDS/PPM meters read exactly the same thing, Electrical Conductivity.

Elemental ppm isn’t measured by an ec meter. Elemental ppm is the actual, real parts of a particular element per million by weight. Yes I’m well aware that ec and tds and ppm “meters” read the same thing.

 

[nxsov180db]

It's the same thing just presented with different units. If anything ppm is a lot more accurate if each point really made a difference. It's like measuring with a tape measure, (EC), or micrometer, (PPM). I don't worry about my nute sol'ns being ± 50 ppm so an EC reading would be close enough for that. When I was in a lab testing water for heavy metals to PPB each tiny point matters.



EC and TDS/PPM meters read exactly the same thing, Electrical Conductivity.

In other words elemental ppm is the “real” ppm which can’t be measured by a meter, if I’m feeding an elemental ppl of 450 and ppm meter (which is just measuring conductivity) will probably tell me it’s 550.

 

[OldMedUser]

I give up.

 

[RookieMuffin]

I use Lucas for dwc, but right now I'm using the h3ad formula in coco. 1.7 ec is what I get when I'm done mixing. My plants love it, and I can't take it lower without deficiency. FTW! Lol

Nice to hear that you have the same problem when diluting the lucas formula to a lower EC lol!

Can you tell me at what strength you use the lucas formula? 100%? And what about your setup? What lights and wattage and so on are you using?

 

[RookieMuffin]

View attachment 5264590

I used this chart and got great results which is 1.4 EC on light feed. I have not messed with my ec meter in months but from what I recalled it was on the low side of the estimate (1.4ec in this case) because distilled as you know, is pure.

At first I thought ok you got .5 EC just about from the 1:1:1 like ratio which is right. But to say you are getting 1.7 instead of 1.4 or 1.5 then that is weird unless it is because you are using a formula that is not as detailed as this feed chart posted.

For example, following a personalized feed chart now relies on that person answering directly why their EC is a certain way. Was it well tested like this manufacture? What water was used, distilled or filtered mineral water? I am learning right now how the chemistry is more complex than I thought.

Reactions happening at all times. But if you followed this chart by your manufacture, you would probably get the same EC range but they assume you know the EC is just a sign of strength. I add .5 ec from my tap and get 1.9 - 2.2EC and was fine even through flower.

Some ingredients I thought have higher EC than others too don’t they? calmg adds .8 EC for example. Lucas, isn’t that like just two of the 3 flora trio? Last time I looked I thought it was, might explain too.

PS if you have plant issues, just showing pics and info on what you’re doing to them goes a long way, others might point things out that you wouldn’t of otherwise known. Not sure how long you grew ( I haven’t all that long) but hydro, plants should be growing/uptaking aggressively.

Yes Lucas uses just 2 of the 3 bottles and I have nice results using it. I'm using it for a long time so yeah I like it very much lol.

I already have threads where I've discussed the deficiencies with pictures and I've already talked with a lot of people over here and I already solved the deficiencies.

This question was not about deficiencies it was about why my EC meter shows a higher value than what I've calculated with math with infos of how much nutrients are in the fertilizer with the label on the fertilizer bottle.

So yeah my plants are already healthy right now. I figured out I need a higher EC than most people recommend. Since then my plants are happy without supplements!

The other variable is that the %'s listed on the bottle may not be accurate. The numbers that manufactures are required to list are the minimum guaranteed % by weight, but nothing prohibits them from putting more.

Ahh that's a nice info! Thank you that might be happening too! So it may be a mix of elemental forms and more nutes in the bottle than what the label says!

A friend used GH 3-part years ago and when he got new batch he fed the same but got really bad nute burn. He still had some of the older stuff left over so we did some testing and found the older stuff to be much lower than the new stuff which was higher than what was listed on the bottles. Kinda like a hot-shot that kills junkies.

There are also buffers added to nutes that will raise the ppm higher than the listed nutrient levels. That would explain why the EC/ppm readings are higher than what the calculated readings say it should be. As they don't list those you can't factor in their influence in the calculations.

Thank you too dude! Your story and the nute buffers is what might be going on! That's what I was thinking too! Maybe the nute buffers (which aren't listed on the bottle) might raise the EC higher! And that might be why my plants were deficient with lower EC but after I've calculated how much NPK and so on was in my nute solution I know why they are deficient. EC was ok but Nutes were to low. So yeah I think there might be other things like nute buffers which rase the EC and that's why I have a higher reading with my meter than what I've calculated based on the manufacteurer label. Thanks!

I've found EC of about 0.5-0.8 for 'teenage' plants, slowly raising up to about a peak of 2.0 in through late Veg to mid bloom, maybe 2.3 at the extreme, but then tapering that back down in late flower to about 1.3 - 1.5 works well, which is roughly inline with the guidence on my particular nutes...

Once you're above EC 2.3 you are getting seriously hot on the nutes (depending on the nutes you are using, there will be some variance, and certain plants will tollerate more than others).

https://www.shogunfertilisers.com/media/4qqbun3d/shogun_-_hydro_feedchart_new.pdf

I didn't raise a lot since they were seedlings because people told me to use low EC which is better than high and so on... Yeah now I'm using more like you said and they are happy! 1.7 EC right now instead of 1.0 before.

Another thing to keep in mind is the rh. With chronically low rh like we have up north here I was getting toxic salts buildup over time that would show up mid-flower with older fan leaves going all orange/brown all becoming all thick and crunchy. That would just keep getting worse until even the small bud leaves were fried. At low rh the plants are drinking lots more water and pulling up a lot more nutes than the plants can use so it gets stored in the leaves until the levels become toxic and the leaves burn all over their surface rather than starting at the edges and working inwards.

Like right now the rh in my little veg tent is 31% while the rh here in the mancave is only 17% and both can go lower than that. The way to manage that is either humidifiers, big PITA, or feed at lower levels so the plants can utilize all the nutes that they pull up with the water and not store extra.

RH is like 50-70 so I think I'm in a better range lol!

Elemental PPM will always be different than the electric conductivity conversion

I don't really convert the EC I only measure in EC not ppm. But yeah I now know that the calculated elemental PPM is different but I think it was a good step to calculate them to see why I was getting deficient plants!

Yeah That's an intersting question, I've always gone with EC for simplicity, as there are several ways of measuring PPM. I'm kinda on the fence as to whats best, but I'm just gonna stick with what I'm accustomed to for now!

I think EC is better to! No conversion problem and everyone on earth talks about the same 1.7 EC... When people talk about converted ppm it's not the same and most of the time they event don't specify the conversion factor which makes it worse lol! If they would always include the conversion factor it would be better. So yeah I think EC is easier and better!

EC is still accurate as an indicator of nutrient concentration so there’s really no need to pay attention to total elemental PPM for most growers.

For me it was. Calculating the total PPMs of each nutrient showed me why my plants were deficient. It wasn't because of one single element was to low and I should supplement it... It was because it was not enough nutrients overall so I had to use more nutes instead of just supplementing.

Elemental ppm isn’t measured by an ec meter. Elemental ppm is the actual, real parts of a particular element per million by weight. Yes I’m well aware that ec and tds and ppm “meters” read the same thing.

Thanks for clearing that up again! Elemental PPM is what I've calculated based on the manufactuere label! And the EC is what I've measured with a EC meter.

In other words elemental ppm is the “real” ppm which can’t be measured by a meter, if I’m feeding an elemental ppl of 450 and ppm meter (which is just measuring conductivity) will probably tell me it’s 550.

That's what's going on on my side. Like you and some others said it's not a fauly meter. The meter just measures everything. And I've calculated only the real elements. That's why my EC reading is higher and the calculated value is lower.

 

[nxsov180db]

Thanks for clearing that up again! Elemental PPM is what I've calculated based on the manufactuere label! And the EC is what I've measured with a EC meter.

Im glad you got it, the other guy that kept telling me EC and PPM meters measure the same thing wasn't understanding the point lol.

 

[futurebanjo]

Im glad you got it, the other guy that kept telling me EC and PPM meters measure the same thing wasn't understanding the point lol.

But they do measure the same thing, they just use different scales of measurement, for example temperature in centigrade Vs Farenhight.

It's an electrode, it can only measure Electrical Conductivity.. (salts in the water in this example).