K
kushtrees
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Alright first off, some questionsIve been using the jacks, cal nitrate, epsom salt combo for awhile now, but I have been battling large pH swings for awhile, its gotten so bad that I will pH the res to 5.6 and in 24 hours its up to 6.2 (DTW btw).
I am using the 3-2-1 ratio at 60% with 2.5ml/ gal dynagrow protek, as well as fulpower and root excel (but I doubt those last 2 are causing the pH swings); this comes out to 1.2 EC. Run off is at 1.1 EC and currently at a pH of 7.3....
I am going to loose the silica next week to see if I can get the pH in the res to stabilize, I also plan to flush the medium really well to try and get a clean slate in there so to speak. After that, assuming that things stabilize and the plants start to look a little better, I plan to bring back the silica at 1.25ml/ gal and see if that will keep a steady pH.
Has anyone else experienced massive pH swings when using silica and Jacks? My guess is that the lower than usual EC with the normal dose of silica is the culprit here, but I wanted to see if anyone else has any ideas or has seen this before.
PS I am using 2 kinds of chow, 1 group is in 80/20 growstones coco, the other is in 80/20 growstones SS4.
Jacks has no Si by itself, the improved branch strength you have is most likely from the increased amount of Ca you're providing to your plants compared to other formulas. Understandable how one could interpret that as Si.Jack's has more than enough silica own it own. I can attest to this as my branches are thicker and stronger than ever.
Jacks has no Si by itself, the improved branch strength you have is most likely from the increased amount of Ca you're providing to your plants compared to other formulas. Understandable how one could interpret that as Si.
A 3.5mM K solution is ~136.5ppm K. Out of curiosity, what were you reading that mentioned the 3.5mM K solution? PM me plz, to not completely jack thread.this is a huge threadjack, but if I wanted to make a gallon of 3.5 mM K solution, would I add 0.5273 grams of K to a 1 gallon jug and fill it up with water?
Just trying to wrap my head around the math of things.
Jacks has no Si by itself, the improved branch strength you have is most likely from the increased amount of Ca you're providing to your plants compared to other formulas. Understandable how one could interpret that as Si.
I could really go into details on how to tweak your nute profile to be more optimal for your plants, but idk if you're interested in the topic or what i have to offer. I like Jacks Professional (I use it myself), but im not a fan of the 3-2-1 usage of it thats gotten popular amongst its users. Its works just as well as most other nutes that are orders of magnitude more expensive than it, its just not optimal IMO.
http://www.usu.edu/cpl/research_hydroponics3.htm
Lol. im a stoner, i thought it said your were running RDWC instead of DTW. I use DTW as well and use ~15ppm Si myself. But i have enough AgSil16H to last til i die and @ 15ppm it doesnt give me any pH/alkalinity issues. Also using NH4 wont help you control pH in your solution if using DTW, but it will help control pH in your medium, which matters more but wont help you control your solution pH which is what you originally asked, however the other things i mentioned will still help control pH of both your solution and medium.I currently use RO water. I had read that 25-50 ppms of silica was what you wanted. 3ppms is much much lower, but I will definitely be trying 3ppms. I'm very into the less is more philosophy these day, especially with nutes
Thanks for pointing that out. I thought OP said RDWC for some reason.Your link was a good read, though it's quite specific to recirculating systems, while OP mentions running DTW.
I'm also interested in your opinion on how to use Jack's Pro to create an optimally balanced nutrient profile for cannabis. Please share.
this is a huge threadjack, but if I wanted to make a gallon of 3.5 mM K solution, would I add 0.5273 grams of K to a 1 gallon jug and fill it up with water?
Just trying to wrap my head around the math of things.
3.5mM = 3.5x10E-3 moles / Liter
Atomic weight potassium nitrate = 101.1032 g/mol
3.5x10E-3 mol X 101.1032 g/mol = 0.0035molX 101.1032 g/mol
= 0.35386 g
0.354g / L = 3.5mM KNO3
1 gallon = 3.78541L
0.354 g/LX 3.78541L/ G = 1.3400 g/G
Sure.Can you do that again with just K?
Sure.
3.5mM = 3.5x10E-3 moles / Liter
Atomic weight potassium = 39.0983 g/mol
0.0035molX 39.0983 g/mol
= 0.136844 g
0.137g / L = 3.5mM KNO3
1 gallon = 3.78541L
0.137 g/LX 3.78541L/ G = 0.518 g/G
Which is, you'll note, pretty damn close to your original figure.
My question is how are you getting "pure" K and then dissolving it? It's possible, it's just super exothermic is all (ie BOOM). The calculations get thrown off when it is a salt, it is important to account for the ion it is balanced with in the calculation. Be it KCl, KNO3, or what-have-you. This is because, in salt form, those ions make up part of the weight you are adding.
ppm only deals in weights which do not correlate perfectly to molarity or molality.
One cares about mass (ppm)
The other cares about molar mass, which is a different measure altogether.
The first can be simplified to mean simply weight solute per total weight solution (further simplified in water due to its density of ~1g/mL).
The second (molarity/molality) cares about moles of solute or the number of molecules which correlates to the atomic masses of its constituent atoms (per liter of solution--regardless of the weight, density, or molar mass of the solvent). We simplify this out (as in the calculation above) to tell us a mass that we input, but it's not as simple as saying how much does potassium weigh and then calculating with only the potassium.
If you want molarity, you need to know the salt and it's molar mass (and preferably whether or not it is hydrated). This is information that the manufacturer should be able to provide for you if it's not included on the label.
You cannot directly convert from ppm to molarity without compound specific information--these are different measures of concentration.
I was just trying to do a calculation. Thank you Squiggly. :)
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