PH is going down...

Is this the proper place for me to ask why my ph has suddenly started dropping? I am using a DWC system I am on day 41 of flower. This is my first grow...


Background: I did have a problem with my nutes on this first grow. I know now that I hurt her with the nutes strength I was using, but she has been a trooper and is very close to harvest. I have been able to set my ph at water change... Do a minor ph down the next day and then she stays rock solid at 5.8.


In the last 5 days, the ph started dropping... Down to like 5.2 over night. Is this normal? Is it nute burn?


I have been been keeping the nutes at 490 ppm. It seems to be her sweet spot. Not going up or down...


Oh yea... RH is running 50%

I have been using Heisenberg's tea... 1/2 a cup every three days and water changes weekly. My discharge water has always been clean. I did a Scrog on her and like an idiot, I'd did not remove the screen when I I let her go. By the time I realized my error, it was too late. I could not get the screen off... Meaning, I have not been able to open the bucket and clean the res. I over nuted her too. I took bad advice on nute ppm. I had her at 1,100 ppm for 4 weeks,before I realized that was for dirt. So, she has had me as her biggest problem. But, ph going down has never been a problem, until recently.


Now I am kind of lost. She is only about a week away from harvest. Her colas still look great. The fan leaves are all dying... What should I do?

If its really a week from harvest I wouldn't even stress it. What's done is done. But just for future reference, running nutrient strengths 1100 ppm and above is not uncommon for dwc. But are you using a digital ph meter? If so I would make sure it's properly calibrated. Seems silly but truth is they get out of whack pretty quickly. I did half a grow like this before I realized. Turns out I was ph'ing my water to about 4.2 instead of 5.3-6. You can imagine the tragedy. Either way, it's too late

Yes, digital everything... Ppm, ph, RH, temp. : )


running the nutes at 1,100 - 1,200 was too much for her. I am letting her tell me if the nutes are right now. I check the ppm every day... If The ppm are rising, I dilute by adding PH'd water. If the ppm are going down, I add back a little. Her sweet spot seems to be right around 490. The ppm stays very stable at that point. I though that meant she is now taking in just as much water as she is nutrients.


Today is day 42 of flower...

I meant to add... The first thing I did was check the calibration on my meter.

the only reason I am asking about the ph dropping, is because that's new. She had not done that before.

Water temp above 70* for extended periods of time could do it... usually when your ph is changing really fast it is because of some biological processes and shit going on in the water / roots. This could be from warm water making the roots like mushy noodles which can open them up to rot which will trigger all kinds of biological activity you won't be able to control with simple h2o2. The roots should be crisp and white with fishbones and the water 100% light proof, clear, no musky smell, and under 70* If the roots are mushy at all or there are a lot of root bits floating around in the water, and with the ph dropping, that is a sign the root zone is not dialed in as far as basic environment. The heisenberg tea can be a little tricky to make if you use too much molasses or not enough, etc. I have had best results with straight Aquashield in water free of chlorine bleach h2o2 etc.

Nutrient issues can fuck with ph too, so I would make sure to run a little cal/mag and use a good complete line that has no organics like dyna gro or general hydro flora 3 part, etc.

I used SensiGrow two part solution for veg and used SensiBloom two part solution for flower. I was also adding Big Bud weeks 2 - 4 of flower. I just orderd cal mag, I have not used it before... But plan on using it for my next grow.

I will ill post some pics tonight when the lights come on.... Her colas do look great, but her leaves are very yellowed. Especially the fan leaves.

Honestly, I am just trying to limp her in to the finish line... This first grow has been an amazing learning experience. I am really looking forward to the next one... At least I won't make the same mistakes again. Lol

Oh... My bucket is completely protected from light ( I learned that lesson very early in this process : ) and my water temps have never been above 70... That I know of.

I have the same issue (5.8 to 4.8 or less in a couple days) as I'm learning about balancing nutes. Getting the perfect balance and keeping levels high without burn for each strain can be tricky. Someone (sorry, I forgot who) in another thread said that during flower the plant is using lots of K which can drop the pH. Since the nute balance is off the K gets used first. I use pH up (Potassium Hydroxide and Potassium Carbonate) so the plant sucks out the K and leaves the water acidic. This is a super simplified explanation. I've spent way more time getting environment worked out so now I get to start the nutrient learning curve.

You should be fine hobbling along a week or so until harvest. If not, I'm screwed too since I'm doing the same thing.

are you using the PH perfect nutrients as well?

machead said:

are you using the PH perfect nutrients as well?

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I don't think I am following your question. Let me go look at the nutrient producers website and see if I can answer this.

no big deal/ just raise ph. check daily. it more then likely are your fertilizer. I had an issue with heavy 16 raisin the ph to way over 7

I would have to say the answer is yer, the nutrients are ph perfect... See excerpt from the website below (I am not advertising)

+ THE SECRET IS IN THE 5-IN-1 FORMULA AND SPECIAL PH PERFECT® TECHNOLOGY... NOW YOU CAN GREATLY SPEED YOUR PLANTS' GROWTH PHASE AND GIVE THEM THE EXTRA-STRENGTH THEY NEED FOR MAXIMUM SIZE, WEIGHT AND POTENCY WHEN THEY FINALLY BLOOM

the sensi bloom (flower nutes) say the same thing.

kinddiesel said:

no big deal/ just raise ph. check daily. it more then likely are your fertilizer. I had an issue with heavy 16 raisin the ph to way over 7

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Agreed... I have not had a problem with it raising ph very high. I do water changes weekly. I have the fresh water at 5.8 and it usually creeps up to 6.2 by the next night. I bring it back down to 5.8 and then it just stays there the rest of the week. At least that is how this entire grow has gone until about a week ago. Then it started dropping to 5.2 over night for like 3 nights in a row. Then it stayed at 5.8 for a couple of days and then started dropping again.


Since the the dropping is a new development... I thought I would ask the experts on here and see of I needed to worry...

says it on the bottles of the base nutrients if u have the ph perfect stuff. If u do u do have problem your lucky ya near the end id say give the whole system a good clean on next rez change, as u shouldn't need to ph there perfect line.

The only thing I have ever found so far in my limited experience with dwc is that when my ph hangs down low for extended time it is always due to funk in my res. Look for bacteria on your airtubes & wipe them down with a saturated Clorox wipe (these work great). Also wipe the lids & above the water line of your bucket/res then add some hydrogen peroxide. Most h2o2 at your local drugstore is 3% so it's mostly water; I add about a half pint per week to keep res clean & stable ph. I reveg my girls so there is a lot of opportunity for funk to occur on mature root systems. I even found yellow bacteria in the connections to my airstones so it's not always easy to see. It looks like white or yellow residue. Your nutes should be regulating the ph with the ppms being so high. I find that in dwc 600-700 ppms is a good number to shoot for...seems like any ppms over 800 is just overkill unless you got 5 foot plants going.

Justforme11 said:

I would have to say the answer is yer, the nutrients are ph perfect... See excerpt from the website below (I am not advertising)

+ THE SECRET IS IN THE 5-IN-1 FORMULA AND SPECIAL PH PERFECT® TECHNOLOGY... NOW YOU CAN GREATLY SPEED YOUR PLANTS' GROWTH PHASE AND GIVE THEM THE EXTRA-STRENGTH THEY NEED FOR MAXIMUM SIZE, WEIGHT AND POTENCY WHEN THEY FINALLY BLOOM

the sensi bloom (flower nutes) say the same thing.

Click to expand...

The plants have changed feeding cycle, she has stopped feeding and has began her last kick at producing thrichs. If there is truly 1 week left its a good time to start a flush or start dropping ppm's. If you just seeing this now I would say you have at least 10-14 days left but without pics its hard to tell ...JAS

JonnyAppleSeed420 said:

The plants have changed feeding cycle, she has stopped feeding and has began her last kick at producing thrichs. If there is truly 1 week left its a good time to start a flush or start dropping ppm's. If you just seeing this now I would say you have at least 10-14 days left but without pics its hard to tell ...JAS

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I will post pics tonight. The lights come on at 8:15 central time zone.

I have a 60x little microscope. The thrichs are almost all clear still. I am only seeing an occasional amber one. The stigmas are almost all still full white. I have my nutes balanced at 490... I was also thinking about going with no nutes starting tomorrow. But now I think I will wait until I post pics here... Your ya'lls thoughts first... : )

You got a week or two more but if there's some amber & you want to pick some bud now go for it. It's better to harvest in stages anyway. I never flush because I usually plan to reveg & don't taste any chemicals in my shit. I think waiting for a proper cure is more important than worrying about flushing nutes. When I change nutes I never add more only ph adjusted water to keep res at proper level. By the time I'm ready to harvest (and/or change the res) ppms should be very low anyway. Some growers swear by flushing but it doesn't seem to matter much IMO.

Oh if your pistils are still mostly white you may even need longer than 2 weeks. Then again once I had a sativa dom that had one bud mostly white pistils even though the trichs were amber as fuck....I let it mature for like 80 days til I finally took it...patience is a mfer

Okay, here are some pics from a few minutes ago.