Why is Ph going Down Now?

I am 3 weeks into 12/12 and over the last week my plants, or res I should say has went from needing a constant dose of ph down, to needing ph up now.... I have some basic ideas, but would like to hear from some well informed pro's so to speak. I am in a double barrel aero mister... 6" barrels 10 feet long with a 36 gallon res sitting at one end filled with about 20 gallons of RO and then ph'd to 5.6 and then maintained between 5.5 to 6.0. I have 6 plants in the room and they are luscious to say the least... ALmost too luscious I would say, but I guess that's like saying I have too much money or too much pussy...... Like I said, I have some basic ideas, but the more knowledge towards the problem, or issue, the better... Oh yeah, nutes are or were sensigrow A&B for vedge with b-52, f-1 and h-2, hygrozime and sensizyme and barricade when needed... now I think I am overusing the barricade. Now that I am in flower, all nuter are the same except for the sensigrow a&B... I switched to Connoisseur for my main and the rest of the additives are the same.... Res temps never above 75, but usually around 72 and room temp I keep around 70 all the time... I get much better results running around 70..... Vortex 6" for fresh intake and vortex 8" for exhaust... Looking for the Earl's and fdd's and Al b's out there to help on this one... I want the true connoisseurs advice

Come on, there has to be someone around that has the knowledge i'm looking for

whats the PPM in the tanks? does it go up or go down? if it goes down the plants are taking more nutes and if it goes up they are taking less nutes and the ph will fall are the roots nice and white? if you have root problems can make your ph change.

9inch bigbud said:

whats the PPM in the tanks? does it go up or go down? if it goes down the plants are taking more nutes and if it goes up they are taking less nutes and the ph will fall are the roots nice and white? if you have root problems can make your ph change.

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Yeah, I bumped from 750 last night to about 950 after I wrote the thread.... They are growing out of control like I stated and were eating more than they were drinking, so I am hoping that is the case. My roots are pretty healthy, but not white do to b-52 and h-2 being so dark it stains the roots.... If it is root rot, doesn't that generally send the ph up?

LOSTCOASTLOCAL said:

Yeah, I bumped from 750 last night to about 950 after I wrote the thread.... They are growing out of control like I stated and were eating more than they were drinking, so I am hoping that is the case. My roots are pretty healthy, but not white do to b-52 and h-2 being so dark it stains the roots.... If it is root rot, doesn't that generally send the ph up?

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if they are eating your ph will rise they are taking the nutes and thus the ph will rise because the salts in the water help to lower the ph. e.g you take a ph reading of your water and it is??? lets say 7.8 now you mix nutes and take a reading and its now ph6 the salt lowers the ph now that water is being feed to your plants and they are sucking up the nutes what going to happen?? the ph he will rise because of less salt in the water.

stick your nose in the tank does it smell real bad? if not then you dont have root rot it does not sound like it to me the way you are talking about how good your plants are looking. keep on doing what you are doing if its working and the plants are looking good.

9inch bigbud said:

if they are eating your ph will rise they are taking the nutes and thus the ph will rise because the salts in the water help to lower the ph. e.g you take a ph reading of your water and it is??? lets say 7.8 now you mix nutes and take a reading and its now ph6 the salt lowers the ph now that water is being feed to your plants and they are sucking up the nutes what going to happen?? the ph he will rise because of less salt in the water.

stick your nose in the tank does it smell real bad? if not then you dont have root rot it does not sound like it to me the way you are talking about how good your plants are looking. keep on doing what you are doing if its working and the plants are looking good.

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I know I know.... These stupide meters have becme lifelines to me like my cell.... I refused to have a cell for years, then once I had one and lost it I felt naked.... I have never used meters untill the last year, and now if it's not spot on I find myself always questioning why..... Not much info on here at all for why ph drops.... You usually only hear about it rising.... And yeah, I don't have any stink and was pretty sure I had and have no root rot. Just one of those people that goes nuts over anything they can't understand

oh yeah, by the way.... I hear opposite of the whole rise and fall of the tds.... I heard if plants are heating more than they are drinking the ph will go down.... and my tds was dropping along with the ph. was not going up like you had suggested.... Just thought I would relay what I heard, but could very well be tangled somewhere along the lines

LOSTCOASTLOCAL said:

oh yeah, by the way.... I hear opposite of the whole rise and fall of the tds.... I heard if plants are heating more than they are drinking the ph will go down.... and my tds was dropping along with the ph. was not going up like you had suggested.... Just thought I would relay what I heard, but could very well be tangled somewhere along the lines

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my ph as never fallen its only goes up may be its the nutes you are using? hard or softwater can make ph unstable if for i.e you use hard water nutes and you have softwater and vice verser.

9inch bigbud said:

my ph as never fallen its only goes up may be its the nutes you are using? hard or softwater can make ph unstable if for i.e you use hard water nutes and you have softwater and vice verser.

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Naww, I use RO with all AN nutes.... Ph always went up slowly untill last week. Then started this decline.... Lights are going to kick in a half hour... Am interested to see where it's at now after bumping nutes last night

LOSTCOASTLOCAL said:

Naww, I use RO with all AN nutes.... Ph always went up slowly untill last week. Then started this decline.... Lights are going to kick in a half hour... Am interested to see where it's at now after bumping nutes last night

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just a thought when was the last time you changed the nutes? for a fresh batch?

9inch bigbud said:

just a thought when was the last time you changed the nutes? for a fresh batch?

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week ago. I add at least two fresh gallons each day too and just added 6 more just now.... When I went to bed last night it was bouncing at 5.6-5.7 and when I checked it at 7:30 tonight when the lights kicked on, it wasdown at 4.8-4.9.... I added the fresh 6 of RO and used the barricade to get back up to 5.6..... but this is driving me crazy

it not rot, its the uptake in nitrogen that is causes it, just keep an eye on your roots.5 week of flower my girls make thier ph shoot down to 5.2! i have shot 15 mls of ph up and the next day its down again. just them using more phosphorus, etc..

NEVER OUTGUNNED said:

it not rot, its the uptake in nitrogen that is causes it, just keep an eye on your roots.5 week of flower my girls make thier ph shoot down to 5.2! i have shot 15 mls of ph up and the next day its down again. just them using more phosphorus, etc..

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yes exactly that, ive had this on all my aero grows, ph goes up during the mad stretch at the start of 12/12 cycle and again RAPIDLY decreases during the peak of flowering at around about the 5th week (depending on strain) when this happens its usually a good indicator to get the pk13/14 out and use untill the ph starts dropping at a much slower rate, then i ussually change the res for a fresh batch and let them finish up. if the roots are healthy the ph drop/rise is good, i find this is a definate benefit of a recurculating system that you can read what the plants are doing just from the resevoir, run to wastes dont offer the same advantage cheers

the fall guy said:

yes exactly that, ive had this on all my aero grows, ph goes up during the mad stretch at the start of 12/12 cycle and again RAPIDLY decreases during the peak of flowering at around about the 5th week (depending on strain) when this happens its usually a good indicator to get the pk13/14 out and use untill the ph starts dropping at a much slower rate, then i ussually change the res for a fresh batch and let them finish up. if the roots are healthy the ph drop/rise is good, i find this is a definate benefit of a recurculating system that you can read what the plants are doing just from the resevoir, run to wastes dont offer the same advantage cheers

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Sorry to bring up an old thread but im having this same problem. Its not root rot but ph going down. Another site said to lower nutes and that N and K are being used while leaving P behind making it more acidic. You say to add more PK which would make it worst according to the other site i thought. Can anyone clarify this and what to do. Im 5 weeks into flower northern lights dwc using Gh nutes.

Lost: I had the same problem on my last grow, and it was the first time. I pestered everyone I knew and got all kinds of ideas, although none of them were right. Finally one of our teachers said, " Don't stress, if your plants look happy just correct it back to 5.8 and go with it." I did and I had one of the best harvests ever. I hope that helps. HSA

Same problem here with Aerogarden, RO'd water. Heathly plant about 4 weeks in and PH keeps going down. I add a small amount of PH up almost daily. The plant looks great however!

Why pH Varies The ratio in uptake of anions (negatively charged nutrients) and cations (positively charged nutrients) by plants may cause substantial shifts in pH. In general, an excess of cation over anion leads to a decrease in pH, whereas an excess of anion over cation uptake leads to an increase in pH. As nitrogen (an element required in large quantities for healthy plant growth) may be supplied either as a cation (ammonium - NH4+) or an anion (nitrate - NO3), the ratio of these two forms of nitrogen in the nutrient solution can have large effects on both the rate and direction of pH changes with time. This shift in pH can be surprisingly fast. Daylight photosynthesis produces hydrogen ions which can cause the nutrient acidity to increase (lowering the pH). At dusk photosynthesis stops and the plants increase their rate of respiration and this coupled with the respiration of micro organisms and the decomposition of organic matter uses up the hydrogen ions so the acidity of the solution tends to decrease ( pH rises ) (weedfarmer.com)

Ilovebush brings good info to the table.. You have alot going on here. Did you mention which medium you are using if at all? If it were me, the simple fix would be to lose all the additives, switch to Dyna-gro flower, mag-pro, and protekt (silica) and you're ph will likely be rock solid and you'll get some nice results. In that case you can also add 6 drops of bleach to your solution and be damn sure you don't have root rot. I know that is probably not the answer your looking for, but I just like simplicity and good results when it comes to nutes. You won't catch me with a bunch of bottles of crap, it always turns into crap, not to mention all of the money down the drain. Forgive me if my advice is too off base and drastic for the type of fix you were looking for. Good luckeither way, the good news is apparently the topside is still looking awesome- cheers to that!

PS- you may just be running too hot for the amount of water transpired and the plants are drinking faster than they are feeding, which causes fluctuations in the ph as the solution becomes more concentrated... Try lowering PPM's and see if it doesn't sort some stuff out.

HSA said:

Lost: I had the same problem on my last grow, and it was the first time. I pestered everyone I knew and got all kinds of ideas, although none of them were right. Finally one of our teachers said, " Don't stress, if your plants look happy just correct it back to 5.8 and go with it." I did and I had one of the best harvests ever. I hope that helps. HSA

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This little bit of information is not used enough here. Thank you for saying sometimes you have to go day by day and ride it out. You can tell people who are experienced and arent so quick to start throwing in this and that, make this change and that. Sometimes, most times, I just watch the upward growth, make sure that's ok, and adjust the ph as needed, instead of trying to figure out something that may not have an answer, or just do a res clean with new water, run that a day, wash it out, and make a new batch and go from there. Too much babysitting of a plant that naturally takes tough environments well.

Baby them too much and they will need to be taken care of like children instead of a plant .

Guys people that are somewhat new to growing aren't able to understand half the highly educated answers that are given on here, people get freaked out. Advanced cultivation is where that conversation is great for.

bowlfullofbliss said:

This little bit of information is not used enough here. Thank you for saying sometimes you have to go day by day and ride it out. You can tell people who are experienced and arent so quick to start throwing in this and that, make this change and that. Sometimes, most times, I just watch the upward growth, make sure that's ok, and adjust the ph as needed, instead of trying to figure out something that may not have an answer, or just do a res clean with new water, run that a day, wash it out, and make a new batch and go from there. Too much babysitting of a plant that naturally takes tough environments well.

Baby them too much and they will need to be taken care of like children instead of a plant .

Guys people that are somewhat new to growing aren't able to understand half the highly educated answers that are given on here, people get freaked out. Advanced cultivation is where that conversation is great for.

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Amen! Common sense 101- do you see Miss Suzy with her garden next door stressing about all her carrots all the time? It's just a plant too.