Ok @GrouchyOldMan lets talk about dosing pumps.
I see the value for maintaining pH and/or EC.
However, if you are dosing to maintain levels, then all of that Water-level/pH/EC falling/rising/stagnate guidelines in that chart go out the window. I know I use the hell out of that chart to let me know when to increase nute or whatever.
So, if you are using a dosing pump to maintain parameters, how do you know how well your plant is doing and when to increase/decrease nutes?
Great question! Iām betting itās just like any other new tool in our kit, you experiment with it, learn how it behaves and then adapt it to the work at hand.
Perhaps the more important question is whether it is actually feasible to fully automate pH control in our various hydro system setups? I donāt know, but if it is then weāll need a tool like this is described. Right?
FWIW, the Amazon reviews for this Milwaukee system are very informative. Folks have been using it for a long time now and they seem to be able to get pH dialed in using it for some fairly complicated applications.
Itās probably overkill for small cannabis hydro systems, but at $250, the barrier to entry isnāt that daunting.
Iām new to this game, eager to learn from those who knowā¦
I have given this a bit of thought for a while. Currently I am able to physically monitor the tent at least twice a day. That has been plenty enough to keep the Rez chemistry on target. Where I become concerned is if I have to leave for a few days.
Adjusted PPM would be easy, use a HM Digital TDS monitor to trigger a dosing pump when the EC is low. I have used this type of control loop for years in aquatics, it definitely works.
pH is bit more challenging. pH controllers that will allow both HIGH and LOW triggers are more expensive as they require 2 outputs and 2 dosing pumps. Less expensive is a single direction, in my case the pH usually rises so I could get by with just adjusting it down as needed.
Another nuance to consider here is I would employee additional logic such that:
Another element I would control if going this far is water level. Just like in wet/dry biofilters, water level changes present themselves in the sump. I would incorporate an ATO controller (Automatic Top Off, prebuilt systems are available in the aquarium sector) to automatically keep the sump at level. I like using a pump and additional reservoir (of pH water) vs float valves hooked to the city water supply. Float valves can have a catastrophic failure mode, where a reservoir (which would run dry) limits that liability.
Just remember the dosing kit only goes 1 way pH up or down. When everything is buzzing along pH up is all you ever need.
With that being said pH for me a a leading indicator of a bigger problem. PH dropping too low to fast letās me know I got some bad bacteria or pests. If I am checking pH every day it gives me a little more time to try to correct the underlying issue, whatever is causing the drop. With a doser you literally wouldnāt know thereās a problem because itās just going to keep balancing the pH for you. Just a little food for thought
Bingo, it makes my Guiding Light Chart below useless. I would have to figure out another way. Like possibly keeping track of how many adjustments are made per day, or how many ml of pH Down got dispensed.
I agree 100%. I want automation but I need data to make the right calls because Lord knows shit donāt always go as planned.
Need a pH doser that monitors and records pH over given period of time oh and itās gotta be cheap, ha.
Great discussion here, the kind of āeducationā Iāve been seeking!
When you treat pH swings as a "diagnostic signal, rather than a āproblem,ā The value of automatic dosing comes into clearer perspective. My thinking was that automating the process would alleviate the ānormalā pH swings that @Reikox described:
Based on your comments, there are numerous other factors that can cause the swings and neutralizing pH with the auto pump would render those undetected.
Is that about right?
ātreat pH swings as a diagnostic signalā is exactly my philosophy. Particularly direction and very important is the Rate of Change (ROC).
@Reikox is right in that āmostā nutes lower pH, and plants eating will raise the pH, but that is not the only thing that could affect pH. For example I have been considering a Dyngro product call Protext, which absolutely raises pH. I have seen pH drift down in my own tent on occasion. I would be afraid to assume that the only pH impact was from plants eating. I believe that DO also affects pH.
Take my last res change as an example. I was having pH swings of 1.0 in less than 24 hours. It went from 5.5 to 6.5 in 20 hours. Had I been controlling pH with a dosing pump, the pH would have stayed at 5.5 ā 5.6 and I never would have been aware of, what I suspect was nute imbalance, until the pH Down bottle went dry.
Automating the pH would have disguised this event.
Now, I suspect that I could extrapolate the ROC by looking at the frequency and volume of pH adjustments, and possibly program the logic for a ROC alarm.
If I ever automate the rez chemistry I would need to somehow make unrealistic ROCs visible.
Day 43:
Soda can for scale.
The smaller one is a female, larger one is yet undetermined.
Glad I started with 4 plants!
I am hoping these last 2 are both female as 2 males presented themselves over a week ago (promptly chopped).
Though I also see that more than 2 plants into flower would not have worked in my 3x3 tent unless I went SOG.
Subbed up.
Tnx for the invite
My general approach to this grow has been to keep the VPD and water chemistry in the āsweet spotā and then just LITFA.
Today however I did remove a few Fan leaves that were shading lower branches, and removed foliage from base of stem. I then added some yoyos to spread the branches out to let some more light penetrate them. Let them bush out a bit.
OMG these two have exploded in the last 2 days. They are so bushy it is almost scary!
DLI 42
Today was warmer than I would like so I had to bump the humidity way up to maintain VPD. Came home to find a bunch of wet leaves. Need to watch Dewpoint levels more closely. Quickly threw a 2nd oscillating fan in there, these suckers are getting so bushy (bud sites EVERYWHERE) I was scared something undesirable might start growing. Also reduced the humidity, which is ok as the heat spell is passing.
Planning my next grow, my current one is about 30 days to chop. Figure my next grow will drop about Dec 1st. Need to empty the tent about mid March so I can get a head start on next years outdoor grow.
If you could only grow 2 plants in the tent, and your focus was on headstash yield, which strain would you grow?
Luciferās Big Buddy Auto Fem
Mephisto Double Grape Auto Fem bx/S1
Northen Lights Fem
Zkittlez OG Auto Feminised Seeds
Acapulco Gold Feminised Seeds
Blueberry X3 Fem
Blueberry Cheese Feminised Seeds
Dos Si Dos 33 Feminised Seeds
Jack Herer Fem
Liberty Haze Feminised Seeds
Purple marmalade x apes in space Fem
White Widow Fem
XO Rasberry Glue Fem Haute Genetic
Durban Poison Fem
Durban Poison and White Widow. The AcGold is a strong contender. Northern Lights is def on my list Iāve smoked so much of it of varying qualities over the years I gotta grow some myself.
Iād still go with Durban and White Widow tho, crazy classic haze head flavors. Big yielders. Maybe start one before the other depending. Donāt you wanna be smoking unlimited Durban Poison and White Widow while tending to your outdoor grow?!
To be more specific, ph should raise in veg and drop in flower.
in veg the plant uses more Nitrogen, which is acidic so as the plants consumes it more than P or K, the ph will naturally go up.
In flower the plant uses more P and K than Nitrogen, both P and K are used as ph up. so as they consume more of those and less Nitrogen, the ph will naturally go down.
If your pH is spiking up in short time periods and/or the water smells bad, both are signs of bacterial growth. Either a chiller or running sterile with calcium hypochlorite, pool shock, uc roots, or something else would be the way to go and you wonāt have that happen any more.
Are these autos youāre growing right now @MrWizard
Yes they are.
Okay cool. I was thinking to myself what a weird timeline for these plants to be about ready in another 30 days 
They are looking really good.
Had to remove the yoyos, cant let these plant spread out any more or they wont fit in the tent.
Cleaned out the base a little more to increase airflow.
I am a big man, with large hands, check out the trunk on theseā¦
True. Itās like shaking hands with some one wearing a baseball glove or one of those āweāre #1ā foam sports team hands.
