PH Drift....why?

[Flash4211]

Hey, y'all. I'm a newbie, a couple of months into my first grow. I have six G13 Haze, grown from seed from Attitude, and they are looking very healthy. I'm starting with distilled water, mixing GH flora/micro/grow along with CalMag and Aquashield to help things along. Growing medium is Hydroton, light is a 4-tube, f-foot T5 6500K. I mix a new 10-gallon batch of nutes once a week, and listen closely to all the wisdom available here and at a few other trustworthy forums.

That said - can somebody tell me why the PH in my res is constantly climbing? I check every couple of days, and it always seems to drift up into the 7.8 to 7.0 range, even though I use PH Down to bring it down to 5.6/5.8 every time. TDS is a pretty constant 800.

Is this constant upward pull on PH a sigh of trouble? Am I missing something in the care regimen? I'm about to move into flower (12/12 in a decent tent with a 1000W HPS); don't want to jeapordize quality of quantity of harvest.

Any advice out there for the ignorant (but enthusiastic!) newbie? Thanks!

 

[chickengutz]

What type of ph down are you using, some products are buffered to the point of uselessness. I mix my own using battery acid, the plants love the sulphur and it is rock steady. You may also want to add a silica additive to your nute solution. While the initial addition of silica will raise your ph, once you bring it down into range it will remain more stable. You may want to explore raising your ppm's as this will help stabilize things. I am one of "those", who never change there rez during a grow so I don't have to address this problem as much as others do, so I'm sure there are other solutions than the ones I've mentioned. Peace and good luck Bro.

 

[jondamon]

Did you wash your hydroton properly before use?

Wash wash wash wash wash.


I have seen upward drifts caused by dry clay remaining in the hydroton.




J

 

[Flash4211]

Did you wash your hydroton properly before use?

Wash wash wash wash wash.

I have seen upward drifts caused by dry clay remaining in the hydroton.

J

You know, even after several complete res changes, I still see some red powder in the bottom of the tank. That's kind of surprising, since when I first got the Hydroton in, I put it in a big sieve and rinsed it with a garden hose for 5-10 minutes, until the runoff seemed to be clear of red residue. Obviously, that wasn't enough. It seems my ladies may be suffering from Premature Saturation!!!

This is great timing. I've just finished building a 2X4 ebb/flow table and loaded it with 50L of Hydroton....which I rinsed about the same way as the stuff my vegging ladies are in. I think I'll run a whole bunch more fresh water through there before doing any transplanting or nute-mixing....

Thank you! That's a nice bit of life-saving info!

 

[jondamon]

You know, even after several complete res changes, I still see some red powder in the bottom of the tank. That's kind of surprising, since when I first got the Hydroton in, I put it in a big sieve and rinsed it with a garden hose for 5-10 minutes, until the runoff seemed to be clear of red residue. Obviously, that wasn't enough. It seems my ladies may be suffering from Premature Saturation!!!

This is great timing. I've just finished building a 2X4 ebb/flow table and loaded it with 50L of Hydroton....which I rinsed about the same way as the stuff my vegging ladies are in. I think I'll run a whole bunch more fresh water through there before doing any transplanting or nute-mixing....

Thank you! That's a nice bit of life-saving info!

No probs.





J

 

[Illegal Smile]

I think if you're using the right nutes you will have no pH problem. I use Humboldt Master A&B. I never worry about pH from 5.5 - 7.0. In fact I seldom check it anymore. It's been over a year since I saw a need to adjust it.

 

[Flash4211]

I think if you're using the right nutes you will have no pH problem. I use Humboldt Master A&B. I never worry about pH from 5.5 - 7.0. In fact I seldom check it anymore. It's been over a year since I saw a need to adjust it.

I've been using GH flora gro/bloom/micro. Do the Humboldt nutes have some kind of ph stabilizer?

 

[cowboylogic]

Did you wash your hydroton properly before use?

Wash wash wash wash wash.


I have seen upward drifts caused by dry clay remaining in the hydroton.




J

Winner, winner, chicken dinner....

 

[Illegal Smile]

I've been using GH flora gro/bloom/micro. Do the Humboldt nutes have some kind of ph stabilizer?

I called them once and got a long explanation that was over my head. The bottom line was that not only do they buffer, but they also are much more forgiving about pH than other nutes. The issue is not pH per se, but that pH too high or too low affects nutrient uptake ability. maybe some nutes are so sensitive that they MUST have pH close to 5.8. Humboldt told me that unless it goes below 5.5 or above 7 or so, not to worry and don't even try to adjust.

 

[Flash4211]

I called them once and got a long explanation that was over my head. The bottom line was that not only do they buffer, but they also are much more forgiving about pH than other nutes. The issue is not pH per se, but that pH too high or too low affects nutrient uptake ability. maybe some nutes are so sensitive that they MUST have pH close to 5.8. Humboldt told me that unless it goes below 5.5 or above 7 or so, not to worry and don't even try to adjust.

Good info, thanks. Their website looks good, too. I'll get some in and try them out after next flush.

 

[chickengutz]

- "Expanded clay has been classified as an inert material with no cation exchange or buffer capacity."
Source: Soilless culture: theory and practice By Michael Raviv, Johann Heinrich Lieth

 

[ChoofyN]

Alright so you did wash your hydroton of all the red stuff, bud did you soak it in pH balanced water for 24 hours? Using hydroton i have found this semi helps with flactuating ph issues as it balances the hydroton causing runoff to be the same as it came in

 

[chickengutz]

and again I post,

• - "Expanded clay has been classified as an inert material with no cation exchange or buffer capacity."
  Source: Soilless culture: theory and practice By Michael Raviv, Johann Heinrich Lieth​

  
  
  ​

 

[ChoofyN]

and again I post,

• - "Expanded clay has been classified as an inert material with no cation exchange or buffer capacity."
  Source: Soilless culture: theory and practice By Michael Raviv, Johann Heinrich Lieth
  ​

  
  
  ​

Ok dude we understand this is what you firmly believe.

 

[Flash4211]

Vincent Price was a gourmet cook as well as a great actor, and many years ago he did a short show on making coffee. I'm very picky about coffee, and paid close attention. He said: "The secret to a great cup of coffee is "fanatical dedication to cleanliness". He's right. Following that logic, it strikes me that fanatical cleanliness is a core concept in growing great herb. Even though expanded clay is theoretically inert, it seems that fanatical cleanliness would mean several washes as well as a pre-soak. Not trying to start a fight, but I think I'll err on the side of caution. As they say, it can't hurt......

 

[Flash4211]

Hi, y'all. This is similar to the issue that started this thread, but with a completely new setup. I've moved five of my ladies into a grow tent 4X4X8, under 1000W HPS 12/12, in an ebb/flow table with thoroughly washed Hydroton. 15 gallon res, GH floragro/micro/bloom mixed to GH's bloom proportions, starting with distilled water. Also 5ml/gal of CalMag, and that's it. I'm feeding three times a day 30 mins each, all during lights-on. There's a big air stone, lots of bubbles, TDS is at 1100. But EVERY SINGLE MORNING, I check the ph, and it has banged up from 5.8 to 6.8! So I add GH phDown until it stabilizes (it actually bounces up before my eyes when adding the phDown, like it's actively fighting the adjustment.).....and the next morning it's back up to 6.8 again. This has been going on for four days now, and the ladies are showing stress, yellow discoloration moving up from the bottom. What could be causing this? It makes me very nervous to keep dosing the nutes with phDown every day like this.

I think I'm going to order a new ph meter, just in case - can a faulty meter act like this? Thanks!

 

[jondamon]

I would now ask whether there is a change in your TDS readings
after the pH shift.

Depending upon what's uptaken by the plant can have an effect on pH. For instance if the plant is taking up K this can cause pH to drop.

Could be the solution is to increase TDS.




J

 

[Flash4211]

TDS has remained pretty steady at 1100.

I just heard the term "ph stabilizer." Is there such a thing, like an additive that decreases ph drift?

 

[Rastaforever]

I use hydroton as medium. This is my 3rd time that I am using the same hydroton. 1st grow the ph rise was 2.00 - 3.00 per day. 2nd grow was always 1.00 per day. Now 3rd grow is 0,4 0,6 per day. I agree with jondamon you have to wash your hydroton very well and if possible let them rest 1 or 2 days in acidic solution (Not plain acidic solution I mean mixed with water) . I am using Nitric acid (HNO3).

 

[lordjin]

and again I post,

• - "Expanded clay has been classified as an inert material with no cation exchange or buffer capacity."
  Source: Soilless culture: theory and practice By Michael Raviv, Johann Heinrich Lieth​

  
  
  ​

Then why do clay pellets cause ph to rise? You get fresh clay pellets, rinse them out thoroughly, soak them in ph 5.5 water, a few hours later the ph is much higher... like 7. I've rinsed hydroton many times and have seen this every time.