Ph fluctuation after res change

[powderful]

Hey,

Running single bucket dwc and I have the strangest thing happening.

I was giving one of my white widows an air-bath and doing a res change and then the ph was way up after adding the plant back.

Procedure:

Set water out for a few hours [7,6]
Add nutes (mixing well between A and B)
Add epsom salt
Leave for an hour [7,06]
adjust ph to 5,69 with about 2.5ml of ph down

Wash res/airstones with tap water and dry off
Let plant air-bathe for about 10-15min
Add plant back.

about 15min later the ph is 6,4

Tap water coming out at about 150ppm with a ph of 7,5
20L buckets with about 14L of water
25ml canna hydro flores A+B (soft)
1 teaspoon of epsom salt (diluted in warm water)
2 X 600W HPS

Roots are white and clean without any smell to them.

I try to keep the res temp to about 68-70 although it has spiked at 72,5 at times.

It has happened before but i attributed it to me being a smarty and mixing my nutes in two 10L buckets to make it easier to pour into the res, I now use a 20L bucket to mix.

I have a grow diary [Jack and the widows] if you need more info, or just ask.

Any input would be appreciated

 

[Cat Jockey]

Typically, a quickly rising pH indicates you are not just farming, but ranching - growing some type of algae, bacteria, etc. But you say your roots are healthy and you don't see any signs of that.

The next thing I see is a 5 gallon res. The smaller the volume of the res, the more unstable the pH can be, most definitely with tap water. Add to that small res your tap water, with a pH of 7.5, and that can compound your problem. I can't give you a definitive answer at this point, but it may very well be a buffering issue with your tap water, if you are certain you aren't growing anything else in your res (like algae, pythium (root rot), etc.).

RO, daddy-o. Switch to RO, and I'll bet you avoid that problem. Ditch the epsom salts, too. I haven't personally used the brand of nutes you are using, but you shouldn't have to add Mg to your res (well unless you are using shitty Botanicare PBP). People that promote such also tend to promote a pH range too high for hydro. 5.6 is NOT the optimal pH for Cannabis in hydro, although in recent years, some nutrient mfgs have catered to that unfortunate myth with their blends, maybe yours, dunno.

That g-damn blue pH chart that St0ney, from the old Hemp Cultivation forum, put out and then got plastered all over the net. If you start your pH at 5.6 every time, you may have Mg issues and think you need epsom (like St0ney did), but the cure is proper pH range, which for hydro runs from about 5.1-5.2 up to about 6.0-6.2.

Not much of answer, but if you are positive there is nothing else in your system growing, you probably have a pH buffering issue with your tap water. I'd start with RO, from now on. Yer ladies will thank you for it ...

 

[powderful]

Thanks for the reply Cat

I've been doing res changes more often than once a week and the res is covered with aluminum-tape and I light checked it by turning it on its head and leaving a bright light underneath and covering any little leaks.

I've been on tap mainly because I didn't have time or money to invest in getting a RO filter installed but next grow it will be the first thing sorted. I also live in a country where the tap water is fairly clean (no fluoride, excess chlorination etc) so I thought it would be fine and the stores don't sell any large containers of RO or spring water.

I too think it is caused by the ph of my water drifting up to its original value. Could this also be a case of spoiled ph down, lowering it only temporary?

I've been doing 5,7-5,8 res changes also because the plants were already at 6,2-6,6 and I didn't want too drastic of a change.

All the charts and advice I have seen states that 5,5 is the lowest for hydro but next run I might do one plant starting around 5 and drifting up to 6 as a comparison.

 

[watts]

What pH down are you using?

 

[powderful]

What pH down are you using?

Canna ph pro down

38% Nitric acid (HNO3)

Says 06/06/2018 on the bottle.

 

[hush]

Honestly, it sounds to me like you aren't dissolving the nutes fully before testing the pH. Yes, the amount of time it takes to dissolve fully might have something to do with your water, but that doesn't mean you have to change your water source... it means, just wait a little longer before you test your pH.

PH down doesn't spoil. It's an acid. The only thing that can really happen is it might evaporate over time, causing it to become more concentrated, requiring less and less of it after a while. But it's just phosphoric acid and water.

Edit: just saw that you are using nitric acid, which I am unfamiliar with, but still, it doesn't spoil.

 

[powderful]

Honestly, it sounds to me like you aren't dissolving the nutes fully before testing the pH. Yes, the amount of time it takes to dissolve fully might have something to do with your water, but that doesn't mean you have to change your water source... it means, just wait a little longer before you test your pH.

PH down doesn't spoil. It's an acid. The only thing that can really happen is it might evaporate over time, causing it to become more concentrated, requiring less and less of it after a while. But it's just phosphoric acid and water.

Edit: just saw that you are using nitric acid, which I am unfamiliar with, but still, it doesn't spoil.

At the start I did make this mistake but now I always give A and B solution a good stir and then leave it for 1-2 hours before i ph adjust.

Should I wait even longer? Maybe the fact that the ph only drops .6 after nutes have been sitting for an hour means they need more time or warmer water to break down properly.

 

[hush]

Should I wait even longer?

Yes, apparently, since when you check it the second time the pH has adjusted further.



My advice is to go purchase a cheap, small water fountain pump and put it in your res or bucket that you mix in. Plug that baby in right before you start adding your nutes. Watch how this makes a huge difference in how quickly everything dissolves.

 

[powderful]

Yes, apparently, since when you check it the second time the pH has adjusted further.

The second time I test it I have put in the airstones and roots so I thought that might also cause the rise but when I change res on the next widow I will:

Heat the water to res temp (65-68)
Add nutes and let it sit till ph stops dropping (measuring once an hour)
Add cleaned airstones and bubble for 15 min while the plant air bathes
Adjust ph to 5.5
Put plant back in and measure ph 1&24 hrs later

Hopefully this should work and I will see a slight rise in ph till I hit the sweet spot with the nutes.

 

[powderful]

My advice is to go purchase a cheap, small water fountain pump and put it in your res or bucket that you mix in. Plug that baby in right before you start adding your nutes. Watch how this makes a huge difference in how quickly everything dissolves.

I have two small air pumps that I use on my jack flash plant, I could unplug one and use it on the nutemix but it is only like 50/LPH. I could buy an aquarium pump at the local pet store but if an air pump/stone will work I will stick with it for this grow.

 

[hush]

Airstones are great... they oxygenate, and they provide a bit of circulation, but nothing like a circulation pump would. I used to have to wait about 2 hours to get a correct pH reading after mixing up nutes in my res... then I put a pump in there and now it takes about 15 minutes.

 

[Cat Jockey]

I've been on tap mainly because I didn't have time or money to invest in getting a RO filter installed but next grow it will be the first thing sorted.

You won't regret that investment. Neither will yer ladies. And your pH woes will go away, most probably.

I also live in a country where the tap water is fairly clean (no fluoride, excess chlorination etc)

I don't. They got that shit so liquored up with fluoride, pharmaceuticals like prozac people have been pissing out, etc. But I digress. Even so, without all of the toxic BS in there, you have got plenty of natural minerals and salts. Lot's of Ca, and such. 150 ppm ain't bad, but it is the alkalinity of what is in that 150 ppm that can jack your pH up.

Keep in mind for the folks that leave their water out in order for the chlorine to evaporate - some places are now using chlorimide. I think it's chlorimide. Regardless of the name, it is a non-evaporating molecule, IIRC.

I too think it is caused by the ph of my water drifting up to its original value. Could this also be a case of spoiled ph down, lowering it only temporary?

Let me preface my opinion on that by reposting a pic I just did in another thread, of a garden I had at one point:

[

That's down a row of a 24 site RDWC in a 10,000 Watt Mother Room, after I had given the girls a little maintenance haircut. Those 24 were lit by 6 vertical MH thowies.

High production Bonsai Mums. RWDC and Cat Jockey style.

As it relates to your question about pH down, I'm not necessarily the one to ask about that, 'cause I threw that shit away years ago. It is on a list of things, like a bottle of Cal/Mag, that are not allowed in my gardens. The significance of all of that is for folks to wonder just how I managed 24 different strains of Sweet Lady Jane on one reservoir and one nutrient solution.

I had probably 60 different strains in that room at any point, and have probably had my hands on 80 different strains (not all strains flowered - with that many, you can be choosy on which strains get space in the flower room) through out the years.

And you can manage multiple strains on the same res, without ever once manually adjusting the pH of the solution or adding any Cal/Mag. I don't mind sayin' those are some pretty healthy girls, displaying no signs of nutrient issues ...

The only exceptions being pure Sativa (rare) and heavy Sativa dominant hybrids (what most lump in with calling a Sativa). Them bitches can be real finiky ...

Now, that being said, I use a base nutrient regime (Macro/Secondary/Micro) that when mixed with RO water starts at the right pH for hydro weed - about 5.2, or so. From there, I let it float to about 6.1, or so, and dump and change. The caveat being that I haven't used your nutes, so I don't know what your baseline with RO is.

Both pH down and up are an easy way to totally fuck up your nutrient solution. When you add it, it percipitates some of the nutrients out of the solution. More importantly, in a healthy system, where one scoffs at the Lucas approach of running one nutrient solution for an entire crop, with only top-offs, like I do, you shouldn't have to manually adjust the solution.

There is a life cycle to your res. A healthy res in a healthy system starts low, and then predictably and gradually, rises over time. At that point, it is spent and should be replaced, not refurbished with top-offs. Not saying that is what you are doing, just pointing out the hows and whys of why I don't use pH Down or Up, and the bad things that come along with using it.

I've been doing 5,7-5,8 res changes also because the plants were already at 6,2-6,6 and I didn't want too drastic of a change.

I understand your logic, but the best way to do that, to not 'shock them', is to reduce the ppm of your nutrient solution (1/2 - 2/3 strength nutrient solution), but administer it at the proper pH, which I claim, is lower than most of what you read ...

All the charts and advice I have seen states that 5,5 is the lowest for hydro but next run I might do one plant starting around 5 and drifting up to 6 as a comparison.

You talkin' about that f'in blue chart made by a cat named St0ney (some copies have his name removed from the corner)? Throw that shit in the trash, right next to that bottle of pH Down (once you switch to RO - you're stuck with it for this grow, though).

My opinion, of course. Not most, though. But I ain't alone. I don't know if 10k is still around, but he'll tell ya the same thing.

That blue chart came from a moderator at the old Hemp Cultivation forum, St0ney. I am making no judgements about him as a person, at all, but at the time, he wasn't an expert grower, just a moderator on a weed forum with an Ebb & Flow grow, and his chart sucks balls. And I say it that strongly both because it is wrong, and it is still, today referred to on multiple weed forums as being 'The Chart' to refer to.

He made that chart after 'solving' his Mg deficiency. His solution, IIRC, was adding Epsom Salts. In addition to the other two, that is another item not allowed in my gardens. If one runs a tub at 5.6, and holds it close to that, many strains will develop a Mg deficiency. Not because there isn't enough in the solution, but because 5.6 is about the point, in the acceptable range where Mg exchange at the roots is occurring least.

Just as their dirt sistern 'Like dry Feet', hydro gal's feet 'Like a good walk'. With anywhere from 5.1 - 6.1-2 being the optimum range. And they like it low. I believe the whole range is necessary, but a lot of good stuff happen between 5.2, or so, and 5.6. or so, concerning all that ionic exchange stuff goin' on in the root zone at those pH levels.

Weed makes me a bit wordy, sorry for the length. Not trying to sound like an arrogant d-bag. After St0ney banned me from HC (I'm 42 and don't have any issues with St0ney banning me - who the hell cares? Full disclosure is all ..), I landed at OverGrow. After the fiasco there, I actually found a few of my compadres at PlanetGanga. All was sweet until some behind the scenes drama and a fight over who owned the server, or some bullshit like that, and it disappeared. Which is a shame, 'cause there was some good RWDC info there.

After that, I hop on a board, well, not very often. But when I do, I try to throw a few ideas at folks running DWC/RDWC and are still trying to get it all worked out and dialed in. It's all my opinion, feel free to consider it and then take it or leave it. It definitely differs from some and it has worked well for me ...

And I do it on ICMAG 'cause no matter what your personal opinion of Gypsy is, he is a fallen soldier in the WoD. Which is really the War on Who controls the drug profits. Them A-Holes with all the guns and prisons, the International Banks who launder the Black Market drug money, the International Corporations that have a stake in it, the Bloodlines of Europe that still profit off of it, etc. Well them f'ers can kiss my ass. And the horse they rode in on can kiss my ass, too.

All ya'll grow your own. Grow some damn much that you have enough to give to your friends ...

But I digress, again ...

 

[powderful]

Even so, without all of the toxic BS in there, you have got plenty of natural minerals and salts. Lot's of Ca, and such.

I read somewhere that too much Ca will hinder the roots ability to uptake Mg. Is that true?

Keep in mind for the folks that leave their water out in order for the chlorine to evaporate - some places are now using chlorimide. I think it's chlorimide. Regardless of the name, it is a non-evaporating molecule, IIRC.

I checked a few articles and the source water is uv-treated has only trace amounts of chlorine added and not chloramine/chloramide (europe)

There is a life cycle to your res. A healthy res in a healthy system starts low, and then predictably and gradually, rises over time. At that point, it is spent and should be replaced, not refurbished with top-offs. Not saying that is what you are doing, just pointing out the hows and whys of why I don't use pH Down or Up, and the bad things that come along with using it.

I started with topping off to maintain a stable ppm and ph but after reading around and realizing I didn't know what the plant was eating at what levels so now I do ph'ed water top-offs till I have replaced the volume of the res and then I do a res change.

I understand your logic, but the best way to do that, to not 'shock them', is to reduce the ppm of your nutrient solution (1/2 - 2/3 strength nutrient solution), but administer it at the proper pH, which I claim, is lower than most of what you read ...

I thought if ph was increasing and ppm dropping it was eating more nutes than water and that meant it needed more nutes to keep a more stable ph. Did you mean that because I have been feeding her at the wrong ph range she would be shocked if I used the same concentration at a ph range where she is able to "digest" these nutrients better?

You talkin' about that f'in blue chart made by a cat named St0ney (some copies have his name removed from the corner)? Throw that shit in the trash, right next to that bottle of pH Down (once you switch to RO - you're stuck with it for this grow, though).

My opinion, of course. Not most, though. But I ain't alone. I don't know if 10k is still around, but he'll tell ya the same thing.

That blue chart came from a moderator at the old Hemp Cultivation forum, St0ney. I am making no judgements about him as a person, at all, but at the time, he wasn't an expert grower, just a moderator on a weed forum with an Ebb & Flow grow, and his chart sucks balls. And I say it that strongly both because it is wrong, and it is still, today referred to on multiple weed forums as being 'The Chart' to refer to.

He made that chart after 'solving' his Mg deficiency. His solution, IIRC, was adding Epsom Salts. In addition to the other two, that is another item not allowed in my gardens. If one runs a tub at 5.6, and holds it close to that, many strains will develop a Mg deficiency. Not because there isn't enough in the solution, but because 5.6 is about the point, in the acceptable range where Mg exchange at the roots is occurring least.

Just as their dirt sistern 'Like dry Feet', hydro gal's feet 'Like a good walk'. With anywhere from 5.1 - 6.1-2 being the optimum range. And they like it low. I believe the whole range is necessary, but a lot of good stuff happen between 5.2, or so, and 5.6. or so, concerning all that ionic exchange stuff goin' on in the root zone at those pH levels.

I must admit I have been going off forum information and those ph-charts. I thought that if it was incorrect somebody would have put out a better chart. Thinking back I should have done more extensive research on this exact subject.

Weed makes me a bit wordy, sorry for the length. Not trying to sound like an arrogant d-bag.

I can tell you are passionate about this wonderful plant and I fully understand and respect that! I don't get to chat with too many people on this subject (loose lips sink ships) so I welcome the information

After that, I hop on a board, well, not very often. But when I do, I try to throw a few ideas at folks running DWC/RDWC and are still trying to get it all worked out and dialed in. It's all my opinion, feel free to consider it and then take it or leave it. It definitely differs from some and it has worked well for me ...

And I do it on ICMAG 'cause no matter what your personal opinion of Gypsy is, he is a fallen soldier in the WoD.

I for one am happy that experienced growers like yourself take the time to answer us noobs and encourage us and ICMAG has been one of my best resources through this horticultural adventure!

 

[powderful]

Well I have let the solution sit for 2 hours now and after a vigorous few minutes of stirring it is still at the same ph as it was just after I finished mixing it

I did add half a teaspoon of epsom but I don't think that would cause it not buffer lower. I could be wrong though hehe

Not quite sure if I want to discard this mix to check since I don't have anymore aerated water handy till tomorrow.

Guess I will give it another hour and some more stirring and see if it makes a difference.