"Runoff pH is useless" or "Keep an open mind"?

The statement that "runoff pH is useless" is going around RIU. It seems to be a statement which clearly states 100% lack of usefulness.

I have an open mind about runoff pH. While I don't use Hydrobuddy, I do use a spreadsheet and make my nutes from scratch. It's a PITA, tedious and time consuming, and requires concentration to avoid mistakes. I've been able to successfully alter runoff pH by altering the nute's nitrate:ammonium ratio. I didn't discover this, instead read about it. I thought it common knowledge that ammonium sulfate (AMS) was acidifying, but maybe that knowledge was due to my lawn-care background. Manipulating the ratio of nitrate:ammonium in my nute formulas seems to change runoff pH in predictable ways. Therefore, the statement "runoff pH is useless" is false. You can certainly argue its usefulness, but useless means it lacks any usefulness.

For those who buy their nutes in easy-to-use nutrient bottles and who are not trying to change the manufacturer's designed nitrate:ammonium ratio, maybe tracking runoff pH is useless. I don't know. Here's one RIU post which may explain the rationale behind the statement "runoff pH is useless":


The poster said that a soil slurry test is preferable to runoff pH. Maybe it is, for measuring potting mix pH. Is that the same thing as runoff pH? Taking a small core of potting mix which has a plant actively growing in it will likely damage some roots.

The scientists who wrote the following report used runoff pH as a data point:

Although the pH of applied irrigation water does not directly translate to the pH of greenhouse or nursery runoff, few studies have characterized the quality of irrigation runoff on a nationwide basis

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It is my belief that since I can alter runoff pH by altering the nitrate:ammonium ratio, I should set runoff to a pH value which cannabis plants are known to like and where good mineral absorptions occur. Will it make any difference in the overall performance of my grows? I don't know.

For those who believe "runoff pH is useless," would you mind pointing to any peer-reviewed journal reports which make that assertion?

I never check it and my plants are perfect.

I believe that the "poster' in question meant in l.o.s. you don't water to runoff therefore, it's unnecessary.

Hollatchaboy said:

I believe that the "poster' in question meant in l.o.s. you don't water to runoff therefore, it's unnecessary.

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l. o. s.?

CatHedral said:

l. o. s.?

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Living organic soil

Hollatchaboy said:

Living organic soil

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Thanks I thought something different and wrong.

CatHedral said:

Thanks I thought something different and wrong.

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No problem man.

CatHedral said:

Thanks I thought something different and wrong.

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My bad anyways. I'm too lazy to type shit out. Lol

If your using salts and have a problem it’s something to check. If your plants healthy then it’s not something worth tracking. If you’re all organic in soil you’re not watering to runoff anyways. Blanket statements are never fully applicable.

My run off test and soil probe test for both ec and ph always go in line with one another. Same goes for slurry test but that is to much effort for me.

also unsure why it’s a big deal to water till runoff in soil/organic, I guess if maybe if a lot of run off? Not sure who does that.

The following is not from a journal, but it is a good read. I've bolded some words in the quote for emphasis.

Analytical data for your grow is extremely important! Make sure that you always have at least two pieces of data before trying to make a conclusion:

1. Concentration (whether it be via PPM or EC)
2. pH

These are crucial tools to analyze in both your runoff and sump. It can keep your plants alive and happy!

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Being the bum I am, while mixing soil not to long ago and noticing that something was not making sense with my blue lab soil ph pen, I just started (gently), pressing a regular ph pen (for liquids), into my soil and it works very well for getting ph.

I have been hesitant to advise because not sure how long your pen will be okay doing this and if it will work for others as well as it works for me but it seems like everything should be fine if your not an animal about it.

haven’t tried with ec pen and am organic now, so i don’t think I will be, I imagine it would work well too

@ mick I just blew you a kiss, I have a feeling you a lacking love in your life and forgot how to behave decent.

and wazup you too, one dedicated towards helping you not be so sad all the time.

you are both on ignore, so no need to respond to me and expect me to be able to see it

OneMoreRip said:

you are both on ignore, so no need to respond to me and expect me to be able to see it

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Great........but that doesn't keep me from seeing your posts and warning people you don't know what you're talking about.

OneMoreRip said:

Being the bum I am, while mixing soil not to long ago and noticing that something was not making sense with my blue lab soil ph pen, I just started (gently), pressing a regular ph pen (for liquids), into my soil and it works very well for getting ph.

I have been hesitant to advise because not sure how long your pen will be okay doing this and if it will work for others as well as it works for me but it seems like everything should be fine if your not an animal about it.
...

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You might find this helpful,

Because of the sensitivity of the electrodes to contaminants, cleanliness of the probes is essential for accuracy and precision. Probes are generally kept moist when not in use with a medium appropriate for the particular probe, which is typically an aqueous solution available from probe manufacturers.[11][15] Probe manufacturers provide instructions for cleaning and maintaining their probe designs.[11] For illustration, one maker of laboratory-grade pH gives cleaning instructions for specific contaminants: general cleaning (15-minute soak in a solution of bleach and detergent), salt (hydrochloric acid solution followed by sodium hydroxide and water), grease (detergent or methanol), clogged reference junction (KCl solution), protein deposits (pepsin and HCl, 1% solution), and air bubbles.[15][16]

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I haven't gone through any cleaning steps yet, but it's good info to know.

I made up a solution that was close to a 4-mole strength of potassium chloride (I used grocery store bought which has some minor other ingredients, "NuSalt" because I had it in the kitchen anyway), and always store my bulbs in it now. I just fill the bulb cap with it, place the cap, and store the pen upright. It has helped a great deal, the pens don't go out of calibration nearly as much as when storing in tap water. As the water in the solution evaporates, it leaves crystals all over which need to be rinsed off before use.

OneMoreRip said:

Being the bum I am, while mixing soil not to long ago and noticing that something was not making sense with my blue lab soil ph pen, I just started (gently), pressing a regular ph pen (for liquids), into my soil and it works very well for getting ph.

I have been hesitant to advise because not sure how long your pen will be okay doing this and if it will work for others as well as it works for me but it seems like everything should be fine if your not an animal about it.

haven’t tried with ec pen and am organic now, so i don’t think I will be, I imagine it would work well too

@ mick I just blew you a kiss, I have a feeling you a lacking love in your life and forgot how to behave decent.

and wazup you too, one dedicated towards helping you not be so sad all the time.

you are both on ignore, so no need to respond to me and expect me to be able to see it

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Yeah good idea to ignore anything advice from this poster.

Interesting. What ratio of NH4 to NO3 are you using? I’d be worried about the other cations K, Ca and Mg uptake with high amounts of NH4.

Merlin1147 said:

Interesting. What ratio of NH4 to NO3 are you using? I’d be worried about the other cations K, Ca and Mg uptake with high amounts of NH4.

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Right now I'm on 6:1 nitrate:ammonium. I'm finding runoff pH is near 6.3 to 6.5, depending on which inexpensive pH pen I use. That's in a sandy-loam containing potting mix. During bloom I'll try maybe 8:1 or 10:1.

Testing runoff ph in soil is useless.

Testing runoff in coco. Less useless.

Wizzlebiz said:

Testing runoff ph in soil is useless.

Testing runoff in coco. Less useless.

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@OneMoreRip will be deeply disappointed with your post.

simpleleaf said:

You might find this helpful,

pH meter - Wikipedia

en.wikipedia.org

I haven't gone through any cleaning steps yet, but it's good info to know.

I made up a solution that was close to a 4-mole strength of potassium chloride (I used grocery store bought which has some minor other ingredients, "NuSalt" because I had it in the kitchen anyway), and always store my bulbs in it now. I just fill the bulb cap with it, place the cap, and store the pen upright. It has helped a great deal, the pens don't go out of calibration nearly as much as when storing in tap water. As the water in the solution evaporates, it leaves crystals all over which need to be rinsed off before use.

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right on, thanks. that stuff gets more technical than I'm good for. I do clean (with tap water), and use a glorified 'ph probe storage solution', for my meters now.

I've never had a problem with a pen other than an old one going bad, for reasons unknown to me, other than never taking any sort of care of it. Got my moneys worth out of all of them, aside from the bluelab soil ph pen. It seems to me, on the bluelab soil ph pen, the contact area is to small, harder to make contact with the medium and that is why a regular pen works better.

also, from the article 'Very precise measurements necessitate that the pH meter is calibrated before each measurement ', that's a little to much for me but, it may be more direct to lab settings and that, I am not. quick check in 4.0ph from time to time or if mixing any larger amount of anything is good for me.