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Tending Your Reservoir for a Full pH Swing and Cleaner Cannabis

Douglas.Curtis

Autistic Diplomat in Training
So, I received an email back from General Hydroponics this morning following a question I sent in about PH swing vs stability.

Their response: "Static pH is always recommended for best results, tighter it is controlled the better plants can uptake nutrients."

All due respect Doug, but General Hydroponics disagreed.
With all due respect, their opinion means absolutely dog doo doo. I mean how wonderful would it be to hear they're now doing specific testing on cannabis. Oh wait, they aren't doing any testing on cannabis.

Go ahead and ask them the same question again, but tell them you're using plants which are good at phytoremediation and you want the absolute minimal accumulation by the plants possible.


End of story, they sell nutrients and have no idea what constitutes "quality smoking cannabis," nor would it be a stretch to say they've never even seen it in person. ;)

Contrary to what you'll read on the internet posted by lesser educated growers, experienced growers who switch to a pH swing don't switch back. Learn why I'm so adamant about this by doing it yourself. When you get it right it'll be like turning on a bright light in a dark room. HUGE difference.

Be sure to stop back by and share your epiphany.
:tiphat:
 
With all due respect, their opinion means absolutely dog doo doo. I mean how wonderful would it be to hear they're now doing specific testing on cannabis. Oh wait, they aren't doing any testing on cannabis.

Go ahead and ask them the same questioan again, but tell them you're using plants which are good at phytoremediation and you want the absolute minimal accumulation by the plants possible.


End of story, they sell nutrients and have no idea what constitutes "quality smoking cannabis," nor would it be a stretch to say they've never even seen it in person.
wink.gif


Contrary to what you'll read on the internet posted by lesser educated growers, experienced growers who switch to a pH swing don't switch back. Learn why I'm so adamant about this by doing it yourself. When you get it right it'll be like turning on a bright light in a dark room. HUGE difference.

Be sure to stop back by and share your epiphany.
:tiphat:


I will...and thank you!
 

zoo

Active member
Lmfao at using general hydroponics as a barometer for good information on cannabis

They sold out to Monsanto with aims to have their nutritent lines in every homedepot and commercial setting.
 
Lmfao at using general hydroponics as a barometer for good information on cannabis

They sold out to Monsanto with aims to have their nutritent lines in every homedepot and commercial setting.


They designed the nutrient solution (Hardwater MIcro) and I am using it. They've been a very good reference, regardless. Cheers.
 

tilopa

Member
I've been having problems with my rez, I believe. My first run with this system and got what looked like bad nute burn around 6 weeks of flower.

So I came to this forum to post a question, then I saw this thread, read it (most of it) and thought I would ask my question here. The OP seems very experienced and knowledgeable.

Firstly, I'm not using RO water. And I get the strong admonition to use it, but it's not realistic for me to do so at this point. I'm on well water, in a rural town. The water is chlorinated and I use one of those big boy chlorine filters. The water has been tested, and shows no excess of boron, no fluorine, no lead. But it has not been tested for other heavy metal. The PPM is 70 and ph is 6.9. I tested some RO water from the store at it is 0 ppm (of course) and ph is 7.1.

I'm doing flood and drain in buckets with rockwool croutons (little tiny RW cubes). I'm using a 55 gal barrel for nutes. And using Jack's Hydroponic nutes.

Start ppm is 1400, ph 5.8

What is happening is that, opposite from what you experience, my ppm rises after feeding and so does the ph. PPM goes from 1400 to like 1700. PH goes up one point or so.

Also, after about 4 days of feeding the barrel get so low I have to fill it. At first I was just adding water, then I thought I should add nutes instead. My concern is that I'm at risk for nutrient lockout.

Kind of a long rambling question, I know. But, bottom line, I'm trying to get some fundamental practices in place to create a baseline and then refine from there.

So, the TLDR version is:

Is 1400 PPM too high? I'm feeding once a day.
Is it ok to add nutrient mix to the half full reservoir, or will that create nutrient lockout?

Interestingly, I do get the ph swing. If I start at 5.8, after every feed it rises about a point or so.
 

Douglas.Curtis

Autistic Diplomat in Training
I've been having problems with my rez, I believe. My first run with this system and got what looked like bad nute burn around 6 weeks of flower.
This is actually rather common, and is directly related to the large drop in nutrient needs about that time. When running clones, pay attention to this time frame. You'll be able to anticipate it and drop the nute concentration ahead of time, thus avoiding the burn. ;)


Firstly, I'm not using RO water. And I get the strong admonition to use it, but it's not realistic for me to do so at this point. I'm on well water, in a rural town. The water is chlorinated and I use one of those big boy chlorine filters. The water has been tested, and shows no excess of boron, no fluorine, no lead. But it has not been tested for other heavy metal. The PPM is 70 and ph is 6.9. I tested some RO water from the store at it is 0 ppm (of course) and ph is 7.1.
Even though the ppm is only 70, you're noticing a reaction between your nutes and whatever elements are in this 70ppm. Do you happen to have access to the water report on it? Knowing what the 70ppm is can often help. You're basically going to 'find out' how things work with your water, and then create a schedule which works with it. Please post your results over in the discussion thread I have started for tap water and pH swing.

I'm doing flood and drain in buckets with rockwool croutons (little tiny RW cubes). I'm using a 55 gal barrel for nutes. And using Jack's Hydroponic nutes.

Start ppm is 1400, ph 5.8

What is happening is that, opposite from what you experience, my ppm rises after feeding and so does the ph. PPM goes from 1400 to like 1700. PH goes up one point or so.

Also, after about 4 days of feeding the barrel get so low I have to fill it. At first I was just adding water, then I thought I should add nutes instead. My concern is that I'm at risk for nutrient lockout.
Your ppm can go up for at least 2 reasons I know of. First is incompletely washed/rinsed rockwool, and the second is excessive evaporation of water from the nutrient solution.

pH going up may be related to the 70ppm, but again you'd need the water report. I have zero experience figuring things out from a water report, just so you know. :)

Is 1400 PPM too high? I'm feeding once a day.
Is it ok to add nutrient mix to the half full reservoir, or will that create nutrient lockout?

Interestingly, I do get the ph swing. If I start at 5.8, after every feed it rises about a point or so.
1400ppm is about right for most hybrids, and you say you're flooding once a day, correct? I have no idea if that is proper for rockwool, I haven't used it in over 15 years.

I usually mix fresh nutes, and then add those nutes to the reservoir. I have no idea what methods will cause lockout, so I simply add around the same strength and pH of solution.
 

tilopa

Member
Thanks.

I'm going to get a water report from JR Peters company, I'm using there jacks hydroponic nutes. They told me that if you are doing a recirculating water system, opposed to a drain to waste, then it is not a good idea to add freshly mixed nute water to a rez that is in its cycle. The reason is that plants take of elements, for example iron, and different rates than other elements, like nitrogen. Also, as you know they take up some things more than others relative to ph. And when you add more nutes to the rez then that imbalance can become even more pronounced and lead to toxicity of certain elements.

Rockwool has a tendency to create salt buildup, especially in a flood and drain system. And even more so if your room humidity is too low. I live in a dry area and my humidity can be below 40 sometimes. This dries the rockwool too quickly and leaves salt buildup. Trying to figure out how to add humidity but don't want to get a humidifier.

I'm not crazy about the flood and drain with rockwool system. My friend is doing it with great results. I'm thinking of switching to top drip with a mix of rockwool and hydroton, this way I can water several times a day.
 

Douglas.Curtis

Autistic Diplomat in Training
when you add more nutes to the rez then that imbalance can become even more pronounced and lead to toxicity of certain elements.
Yes, this is why I explicitly mention working with a balanced nutrient profile. When you give someone a plate with meat and beans and salad, but there are too many beans for them to eat, the plate has leftovers. This is why nutrient mfgs recommend dumping and refilling after 2 weeks. The solution is to work up a balanced nutrient profile for the plants you're feeding.

Maxibloom and similar nutrient profiles are so close to what cannabis wants, there are no toxicities or imbalances large enough, even after 2 months, to worry about. The plate is clean after each round.

:tiphat:
 

roybart

Member
[FONT=Arial, Helvetica, sans-serif]Snip
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[FONT=Arial, Helvetica, sans-serif]I have run across a few growers who use the opposite pH swing method, through not topping off the reservoir regularly.[/FONT]
[FONT=Arial, Helvetica, sans-serif]Snip[/FONT]
[FONT=Arial, Helvetica, sans-serif]
[/FONT]
[FONT=Arial, Helvetica, sans-serif]I am doing this now. I didn't check the pH this morning tho. It was 7.0 after I topped up so I will monitor it every 12 hours and see what happens.[/FONT]
[FONT=Arial, Helvetica, sans-serif]So far the plants look good and healthy, I did a vigorous LST yesterday and the plants recovered over night. I have a bubbler DWC and I have let run out water. This time around it took 6 days to slurp up 2.5 gallons of water / nutes.
[/FONT]
 

roybart

Member
So far the pH is climbing up to 7.45 for 3 days in a row. maybe I should adjust the pH but the girls look fine.
Tomorrow will be top up day, so I the pH the water after nutes added to 5.0
 

Douglas.Curtis

Autistic Diplomat in Training
So far the pH is climbing up to 7.45 for 3 days in a row. maybe I should adjust the pH but the girls look fine.
Tomorrow will be top up day, so I the pH the water after nutes added to 5.0
If you're using tap water you should start a grow thread and comment there. I recommend starting a thread anyway if you want to track your progress and comment back and forth. I'll be happy to help where I can. :)

If you're using r/o water, the pH rising could be from too much air bubbling through the res, too small of a res for the plant/light size, or not strong enough of a nutrient mix.

Remember, as the nutrients are used up the pH will rise.
 

roybart

Member
I am still playing around setting up the grow room. Doing some basic testing, so the plants I have now are more crash test dummies..lol
 
Using General Hydroponics Hardwater Floramicro...and doing top offs...never allowed the pH to rise past 6.1. Even after a month.

It was set at 5.5 (at first) for about a week and a half and rose to 6, at which point my system needed a top off (pH 5.8).

But pH never rose past 6.1.

After a month, I did a complete change of the nutrient solution.


Ps - This is with hard, tap water, with an untreated pH of 7.6. :) (8.3 aerated)


I wanted to incorporate a regular swing, but it just never happened.
 
Last edited:

Douglas.Curtis

Autistic Diplomat in Training
Using General Hydroponics Hardwater Floramicro...and doing top offs...never allowed the pH to rise past 6.1. Even after a month.

It was set at 5.5 (at first) for about a week and a half and rose to 6, at which point my system needed a top off (pH 5.8).

But pH never rose past 6.1.

After a month, I did a complete change of the nutrient solution.


Ps - This is with hard, tap water, with an untreated pH of 7.6. :) (8.3 aerated)


I wanted to incorporate a regular swing, but it just never happened.
I have no experience with tap water and pH swing, other than it's always different for everyone. I will not be helpful in trying to decipher how a tap water pH swing should be handled.

While I'm definitely interested in everyone getting the best results possible, it just isn't going to happen with tap water.

Everyone has different results with tap/well water, even when the growers only live a mile away from each other. My advice from my experience will not be helpful to anyone.

If you're using water above 14ppm as your starting water, this thread only has a basic idea for you. You will have to totally and completely dissect how your specific water reacts with your nutes and setup.

While I appreciate new information on tap water responses, this is not the thread for it.
I have begun a thread on discussing a full pH swing with tap water. See you there! :)
Thank you.
 
I have no experience with tap water and pH swing, other than it's always different for everyone. I will not be helpful in trying to decipher how a tap water pH swing should be handled.

While I'm definitely interested in everyone getting the best results possible, it just isn't going to happen with tap water.

Everyone has different results with tap/well water, even when the growers only live a mile away from each other. My advice from my experience will not be helpful to anyone.

If you're using water above 14ppm as your starting water, this thread only has a basic idea for you. You will have to totally and completely dissect how your specific water reacts with your nutes and setup.

While I appreciate new information on tap water responses, this is not the thread for it.

I'm repeating this in the original post and doubling the print size, in hopes of reducing this confusion.
Thank you.


I think my lack of pH drift is on account of the chemistry of the Hardwater Floramicro, rather than the tap water itself. Whether the point is moot.
 

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