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New to Photoperiod

Creeperpark

Well-known member
Mentor
Veteran
I set the pH in the very beginning by using cal-mag. I add 12 mls to 4 gallons of RO or Rain and that's enough hydroxide ion to stabilize the water which will give a 5.5 pH. From then on the pH is pretty much set, even after adding nutrients.

I should not be commenting on this thread because I no nothing about coco coir. My apologies.
 

stevebe

New member
View attachment 552694

^As far as affordable ones go these are good and can be calibrated (EC as well as PH). The PH probe actually lasts a long time if you keep it in storage solution.
If you get one that cannot be calibrated, make a video to prove it and get a refund


View attachment 552695

^These are crap, avoid them

awesome, im about a month out from finishing my autos. i cant wait to get rolling with the EC meter. i had a read of that site also. As a scientist i found it very informative. so many of the things that happened to my plants now make complete sense.

i cant believe i never bothered with an EC meter, life just seems easier and all the guess work is taken out :( i burnt sooooo many plants
 

f-e

Well-known member
Mentor
Veteran
So the light was 90w ?
That won't illuminate a 1.2 tent. It might do a 0.5 so that's one nice plant or maybe 4 cuttings as you can flower off cuttings but seeds want to reach a certain age. By which time they are too big for 25cm each. Though some lollypopping can make it happen.
 

exploziv

pure dynamite
Administrator
Veteran
If it's the ts600 light then you would need 4 of it to get close to the needed wattage to run 1.44 sqm. I have a ts1000 (150w model) and i am really pushing it with my 80 x 80 cm canopy.
I'd say 300 real watts per sqm is the minimum light needed for good results, with led lights.
 

stevebe

New member
ive done 4 autos many times with it yielding 30+ grams dry weight per plant. Obviously a massive light would be better. its not an option right now im afraid. All my previous issues point to feeding from what ive now learned.
 

exploziv

pure dynamite
Administrator
Veteran
If it does the job and yelds enaugh for you, then it's all good man. I am happy to hear you were yelding over 1 gram per watt with it, as this is first grow with my ts1000 and I hope I'll have a good yeld as well.
 

Fixer

Active member
The way I mix the feed is by adding the nutrients to the desired EC or PPM level and then adjusting the pH. Seeds don't need food for the first couple of weeks. Clones can be fed at whatever level you feed the mothers. If you're using LEDs add Mg/Cal.:tiphat:
 

stevebe

New member
yeah im not looking do anything insane, its personal use only. but i enjoy trying different strains. ive had many autos between 28-35g dried weight. the problem is i smoke it all too fast :D :D
 

stevebe

New member
View attachment 552694

^As far as affordable ones go these are good and can be calibrated (EC as well as PH). The PH probe actually lasts a long time if you keep it in storage solution.
If you get one that cannot be calibrated, make a video to prove it and get a refund


View attachment 552695

^These are crap, avoid them


soooo i got an EC meter, calibrated it... added my nutes set my ec and then adjusted the pH the EC shot up after adjusting the pH ....... this i think was my initial concern as the citric acid contains anions and cation which will dissociate in water and hence bump the EC. is this normal ? or what do you think is happening here?
 

SuperBadGrower

Active member
Yes, anything you add will raise EC. I've never used citric acid. Using phosphoric PH raises EC by 0.1 or less. In CA is nothing useful for plants. Phosphoric adds about 15-30 ppm P and nitric acid adds about 10-20 ppm N (part of the EC reading). From what I know CA is inferior to phosphoric/nitric in terms of stability (the PH raises faster), and you need more of it to reach the desired PH. I could see it raising EC more than phosphoric or nitric. CA is not recommended in hydroponics. Phosphoric is most used. Nitric acid is option 2, food grade sulfuric acid #3.
 

stevebe

New member
Yes, anything you add will raise EC. I've never used citric acid. Using phosphoric PH raises EC by 0.1 or less. In CA is nothing useful for plants. Phosphoric adds about 15-30 ppm P and nitric acid adds about 10-20 ppm N (part of the EC reading). From what I know CA is inferior to phosphoric/nitric in terms of stability (the PH raises faster), and you need more of it to reach the desired PH. I could see it raising EC more than phosphoric or nitric. CA is not recommended in hydroponics. Phosphoric is most used. Nitric acid is option 2, food grade sulfuric acid #3.

Man i understand very well why it shifts the EC its a mono protic strong acid. HNO3 will do the exact same it also is a mono protic strong acid.
but i mean whats the point to adjust the EC if the buffer is gonna move it ?? do you get me ? its a meaningless task if you set the EC1.2 then adjust PH because its just gonna move as soon as the acid dissociates in the solution. this will happed with EVERY acid as thats what acids do in solution. youve the formation of the H+ ion and the counter - anion which itself is a massive conductor of electrons. It seems to me that people do this routine and then never go back and check the EC ? you cannot have an ec of x value and a ph of y value. the x has a corresponding y value by default you move one they other moves. H3PO4 might be working as its tri - protic due to the fact that it almost never ever gives up the last proton but again the EC will certainly move as the po4 ion is going into solution. :ying:
 

SuperBadGrower

Active member
Ok dude, I really don't know what to say. This is just getting weird. If you want to reinvent the wheel, go right ahead. You realize you are talking to people with years of experience here?

First you add 17 elements to water in such a way that they dissolve and don't precipitate, then you set the PH. There's nothing more to think about.
 

SuperBadGrower

Active member
& Of course people "go back and check" man. there are a thousand threads about PH drift and how to maintain a res over time. Theres people on this forum running 100 gallon reservoirs

Follow the method, use proper tools, and you never have to worry about nutrients. Thats the beauty of hydroponics. You never have nutrient related problems because you control the mediums fertility with every watering.


being honest I'm not sure the level of thought you're putting into it now even really matters when the plants grow in such a low light intensity. 90 watts of led is barely enough to flower stuff in a 2x2 space - actually, we consider 120w the minimum for that size. 30 watts per square foot is still a good rule to go by. Plants that get a lot of light need more nutrients to support photosynthesis. The EC/dosage recommendations for weed basically assume you are working with a light intensity of about one 600 w HPS over a 4x4 area.
 
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stevebe

New member
no dude i appreciate the input its just as a scientist, im a chemist it doesnt make much sense is all. i understand why the EC is being adjust and also the pH but as above they are not independent. so either people move the ec to say 1.2 and move the ph and never go back to see the ec moved or it doest matter ? Vey clearly it does matter ive read a lot about it theres as you said an ideal ec for each stage. I think the best way to explain this is say my ph is to be 5.9/6 this does not correlate to a solution of 1.2 ec. you cant have a solution that acidic and also have the ec that low ? as i said i do very much appreciate your time and everyones here theres a wealth of knowledge. i dont question it works i just trying to understand how it works is al. As for the lights i know the light is not great but ive done 4 plants more than 10 times with the tent yielding above 100g dry. not a huge number i know but its ok for me :) i wouldn't rather figure this EC out like you suggested without changing the light :)
 

SuperBadGrower

Active member
Worry less, I guess. Maybe to understand those things you are better off on a dedicated chemistry forum. For our intents and purposes you are way overcomplicating it.

you cant have a solution that acidic and also have the ec that low ?

For example maybe this statement/question makes sense to chemists but it just makes people like us wonder what you are smoking. Millions or billions of tomatoes, peppers, cucumbers are grown globally in greenhouses each year in this exact style of growing, using nearly the exact same target EC and PH, even element ratios as weed. Thats where I'm coming from. Also CA is definitely not a "strong acid", that might explain a more drastic change over time compared to a more stable ph down which is what most people growing hydro would use. Get a bottle of phosphoric and you might see something different.
 

Fixer

Active member
no dude i appreciate the input its just as a scientist, im a chemist it doesnt make much sense is all. i understand why the EC is being adjust and also the pH but as above they are not independent. so either people move the ec to say 1.2 and move the ph and never go back to see the ec moved or it doest matter ? Vey clearly it does matter ive read a lot about it theres as you said an ideal ec for each stage. I think the best way to explain this is say my ph is to be 5.9/6 this does not correlate to a solution of 1.2 ec. you cant have a solution that acidic and also have the ec that low ? as i said i do very much appreciate your time and everyones here theres a wealth of knowledge. i dont question it works i just trying to understand how it works is al. As for the lights i know the light is not great but ive done 4 plants more than 10 times with the tent yielding above 100g dry. not a huge number i know but its ok for me :) i wouldn't rather figure this EC out like you suggested without changing the light :)


When I mix feed I'm content with 50ppm variance in the concentration of the feed. From what I understand a consistent concentration in the feed relieves the plants of the necessity to change the concentration of the fluid in their root systems to enable osmotic transfer of the nutrients across the cell membrane. So I think you're focusing on the wrong parameter. There are successful growers feeding at EC's of over 4 and those that feed at under 1.2 Consistency is more important that a 20ppm drift in your feed concentration. Good luck!
 

stevebe

New member
Hey man, yeah im just gonna roll with the advice here. Ill order the H3PO4 also it might help. Thanks again for the advice and help guys :)
 

SuperBadGrower

Active member
Consistency is more important

Thats huge! Deserves emphasis


perhaps to clarify - one thing about maintaining a reservoir is that the PH typically goes up, maybe this kind of interaction is what you are thinkin about OP. Like the solution is always changing, reaching some kind of equilibrium or something after we fucked with it (no idea).

So when growers set the ph to 5.6, it's kind of expected that the ph eventually goes up, maybe even to 6.2. And the EC changes too, I dont know too much about that. In my case the ph goes up and EC goes down slightly

Those are maybe some of the interactions that you are aware of, but don't really matter to most of us, because keeping the water good enough for7-10 days is not difficult. :good:

& Finally, dont take people's comments as looking down on your light, just keep in mind that less photosynthesis means there's not as much need for all other things required in the process (water, nutrients, etc)
 

stevebe

New member
Thats huge! Deserves emphasis


perhaps to clarify - one thing about maintaining a reservoir is that the PH typically goes up, maybe this kind of interaction is what you are thinkin about OP. Like the solution is always changing, reaching some kind of equilibrium or something after we fucked with it (no idea).

So when growers set the ph to 5.6, it's kind of expected that the ph eventually goes up, maybe even to 6.2. And the EC changes too, I dont know too much about that. In my case the ph goes up and EC goes down slightly

Those are maybe some of the interactions that you are aware of, but don't really matter to most of us, because keeping the water good enough for7-10 days is not difficult. :good:

& Finally, dont take people's comments as looking down on your light, just keep in mind that less photosynthesis means there's not as much need for all other things required in the process (water, nutrients, etc)

yes you would be 100% correct in saying there is an equilibrium at play. honestly i think i wasn't looking at it the way i should have been. Ive started with the 1.4 ec as im in veg right now as you suggested. What i can certainly say is i needed some more nutrients to bring to this ec and my plants have not burned or locked out :). The advice seems solid. From what i now understand is the ec is only to maintain a consistent feed as you know how much food is in solution every time. Again you were correct in saying bottles can fluctuate. Im now operating the add nutes till desired EC , adjust , then pH adjust.

right now my light seems ok, again depending the strain my buds are never massive, but i know this is down as you said to photosynthesis. Long term ill have to get either another light or a more powerful one. ive another year left of grad school /cry
 

SuperBadGrower

Active member
that's right! Now equipped with that knowledge you can learn to handle any situation. The most important information about runoff water (the water which exists the pot after you pour it in) is the EC value. I never look at the PH of runoff because the plant and the substrate change it..

For example if your input EC is always 1.4 but the runoff is 4 EC at some point. That means somethings gone wrong.


When you are bored you can always look for things like "salinity stress" on scholar.google, reading a few of those helps to understand it

salstress tomato.jpg
for example here is a study where tomatoes grown at 3 EC yielded the most but the 5 EC plants had a higher BRIX value (soluble sugar content or something) = "higher quality"
 
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