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How to tell if you plants like their nutrients via PPM
- Thread starter cosmoline
- Start date
W
Whatever
Neither is more important...it's just understanding what language you're using when talking PPM's. icough2getoff basically explained it...it's like talking English and Spanish in the same sentence...no biggie really. PPM readings are based on a conversion (arbitrary) from EC.mrcheezy503 said:
Agreed.
A point of EC is a point of EC is a point of EC regardless of manufacturer. Sure the formulas will be different (nute ratios and actual macro/micro nutes in the formula).
If your EC is that high in the root zone I don't think you're feeding frequently enough. Yes an EC of 2 in the res ( I actually ran about 2200 to 2400...lol...exact same thing as 2.2 to 2.4 but using micro instead of milli siemens) is pretty normal. I would check my initial runoff from the tables and not the root zone just to be sure. The less frequent you fertigate the higher the EC in the root zone will climb. I mean what about DWC where roots are constantly in a nute solution? The EC is constant...but not when you run cycles in something like rockwool, coco or hydroton.
Hope that helps...
W
Whatever
No other views really...maybe just a communication thing...you can take some GH Bloom and Micro and mix up to get an EC of 1800 or you can take table salt and and mix to get 1800. Either way it's the same EC but the macro/micro profile will be different.bounty29 said:
I basically agree.
Dont the ppms raise as the plants use up water in the evaporation process? I checked my res at day two and the ppms went from 1250 to 1350. I topped it off back to the full mark and the ppms went a lil lower then 1240. Does this sound like my plants are taking the nutes ok? They have great new growth for just two days. You can see the plants in my thread if you want.
I also wanted to say this should be a sticky once more info gets dropped in here. It might actually help growers understand the nutes they are using. PPM knowledge is key in hydro and any other medium as well. Of course it is all strain dependant but maybe we can compile a list of strains and what ppm we like to run them at.
SoSincere
Active member
theres more factors involved than just the simple
PPM goes UP and PH goes DOWN = They require LESS nutes
PPM goes Down and PH goes UP = They require MORE nutes
PPM stable PH goes UP = Good thing
It also has to do with res size to plant count ratio. The larger your res, the faster the ppms will rise and your ph will fall. also if u have good ventillation, evaporation plays a major role
PPM goes UP and PH goes DOWN = They require LESS nutes
PPM goes Down and PH goes UP = They require MORE nutes
PPM stable PH goes UP = Good thing
It also has to do with res size to plant count ratio. The larger your res, the faster the ppms will rise and your ph will fall. also if u have good ventillation, evaporation plays a major role
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jus_chillin
New member
I am wandering the same thing. I have 2 plants growing in a recirculating DWC/DRIP system that holds about 6 gallons of nutrient solution. Either the plants drink up or evaporate between 1-2 gallons of water every 2-4 days. My plants look really healthy - no apparent deficiencies or nute burns. Every few days the PPM rises a lot due to the evaporation/plants drinking. After a few days when I notice the nutrient level has dropped a lot, I add plain water to bring the nutrient level back up to about 6 gallons again then readjust PH as necessary. Is this good??
stillsmokin843
Member
Well I thought the medium you use could make your ppms raise but mabey I'm wrong...hmmm that's what I thought was going on with mine hydrotron was changing the ppms after a flood
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TREE KING
guys so all the directions in this thread is after topping off right? if so then let me ask you guys a question
so lets say my ppm's are at 400 then 24 hours later after a couple waterings i top off my res and then it shows 350. when i add more nutes what strength do i put the ppm at? do i put it back at 400 because it only went down 50 or should i put it at 425 or something.
toohigh, do you use this method to figure out ppm strength or do you have another method?
so lets say my ppm's are at 400 then 24 hours later after a couple waterings i top off my res and then it shows 350. when i add more nutes what strength do i put the ppm at? do i put it back at 400 because it only went down 50 or should i put it at 425 or something.
toohigh, do you use this method to figure out ppm strength or do you have another method?
If EC drops and pH rises, you're under feeding. You'll want to raise EC over 400 not return it to 400. Question is, how much water is being replaced? If half the water, then 450 would return us to 400 but we want more so, we top off with 500 and see where that goes.
Note that EC and pH stable may look good on paper but is bad in practice over time. No single pH reading allows equal absorption of all nutes. By maintaining a flat pH reading, you guarantee unbalanced feeding, leading to deficiencies or toxicity. You want pH to swing between 5.5-6.0. Many swing as low as 5.2. The trick is to slow the swing down to a week or two rather than every day.
Note that EC and pH stable may look good on paper but is bad in practice over time. No single pH reading allows equal absorption of all nutes. By maintaining a flat pH reading, you guarantee unbalanced feeding, leading to deficiencies or toxicity. You want pH to swing between 5.5-6.0. Many swing as low as 5.2. The trick is to slow the swing down to a week or two rather than every day.
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TREE KING
just to be clear when i say top off im talking about pure water. i just wanna make sure your not talking about toping off with water that has nutes in it already.
so how do i know when i have it spot on? if im running 450 ppm then top that off in a day then are you saying it should still be at 450 after that? shouldnt it at least be below the original ppm reading a little? this is what im confused about cause it cant keep saying the same ppm over and over again after topping off, that doesnt make sense
If EC drops (underfeeding) and you top off with tap, you'll lower EC. If they were underfed before, they're starving now. The only way to raise EC with top off is to add a higher concentration in the add back.
Note you do not want flat readings. "Spot on" is highly subjective but, I say it's when pH swings from 5.5-6.0 over a two week period. Measure and chart EC and pH daily, note the swings, if too fast or slow, adjust feed rates accordingly until the swing happens on your preferred timetable.
Note you do not want flat readings. "Spot on" is highly subjective but, I say it's when pH swings from 5.5-6.0 over a two week period. Measure and chart EC and pH daily, note the swings, if too fast or slow, adjust feed rates accordingly until the swing happens on your preferred timetable.
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TREE KING
FreezerBoy the way your explaining this is extremely confusing. im talking about toping off first and then reading the ppm. are you talking about reading the ppm before you top off? thats what im getting when you say "If EC drops (underfeeding) and you top off with tap, you'll lower EC"
gotta run out for a half hour, il be back
If you don't read EC and pH before top off, you cannot top off correctly. Topping off is about more than adding water, it's about adjusting or maintaining EC and pH. If you don't know where these numbers are at BEFORE top off, you have no idea what to top off with.
Measure both EC and pH in the res. Determine what, if any, changes need be made. Draw new water and measure it's EC and pH. Adjust EC and pH of new water so that when added to the res, the res readings are correct. Add water, measure res again to see if desired results have been achieved.
Personally, I overfeed on purpose but, just barely. Over 2 weeks EC climbs, pH drops and straight tap water brings me back to original numbers. However, I wouldn't have known tap water would do if I had not measured EC and pH of BOTH the res and the addback before I topped off.
Measure both EC and pH in the res. Determine what, if any, changes need be made. Draw new water and measure it's EC and pH. Adjust EC and pH of new water so that when added to the res, the res readings are correct. Add water, measure res again to see if desired results have been achieved.
Personally, I overfeed on purpose but, just barely. Over 2 weeks EC climbs, pH drops and straight tap water brings me back to original numbers. However, I wouldn't have known tap water would do if I had not measured EC and pH of BOTH the res and the addback before I topped off.
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TREE KING
ok so your saying to top off with water that has nutes in it. the only way im gonna understand this is step by step directions. can you please explain it like that
so lets say i have a full res at 500 ppm at ph 5.6 then i flood twice in one day. the next day it says 550 ppm with ph 5.8 before i top off. what do i do next specifically? how many ppm do i top off with because you dont want me to top off with plain water right?
I don't know how to explain more simply. Measure both EC and pH in the res. Determine what, if any, changes need be made. Draw new water and measure it's EC and pH. Adjust EC and pH of new water so that when added to the res, the res readings are correct.
EC and pH should move in opposite directions. Something in your medium is messing with the natural order of things if the above scenario is in fact happening. However, because your story is changing, I don't known if the above scenario is true. First EC was dropping now it's climbing. Which is happening? What's the medium?
EC and pH should move in opposite directions. Something in your medium is messing with the natural order of things if the above scenario is in fact happening. However, because your story is changing, I don't known if the above scenario is true. First EC was dropping now it's climbing. Which is happening? What's the medium?
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TREE KING
all you had to do is continue where i left off "so lets say i have a full res at 500 ppm at ph 5.6 then i flood twice in one day. the next day it says 550 ppm with ph 5.8 before i top off. what do i do next specifically?"
i have no idea what your talkin about. thanks for trying anyway
FreezerBoy, whever the ppm is in the res, as the water goes down the ppm gets higher. are you trying to tell me that in your res your ppm gets lower as the water gets lower? i dont know what to say cause that seems impossible. even if i had 100ppm in the res, as the water gets lower the ppm gets higher, that is ""before"" i top off
Your next step is to determine why EC and pH are moving incorrectly.
