Fluctuating pH...

[bkob89]

well, I currently have 6 clones growing in a rubbermaid roughneck 18 gal, using an aeroponic system and well heres a quick recap.

filled my tank with 5 gallons of tap water, added nutes, ppm became 390, ph was 6.8, lowered to 5.8. came home from work about 10 hours later and ph was 7.4...this is not the first time, 3rd day in a row and its confusing me...I did have a water leak which I fixed and this still happens, any advice?

 

[FreezerBoy]

Are you using vinegar? It's only good for a few hours.

 

[bkob89]

Are you using vinegar? It's only good for a few hours.

not using vinegar :/

 

[bkob89]

Again, before I went to sleep set ppm at 400, p.h at 5.9.

Woke up 6 hours later, ppm was 415, p.h was 7.4...

assistance please.

 

[oldschoolfarmer]

Here's an idea:

Fill up your rez and leave it alone for 3 days. Test the ph and ppm every day, but don't add anything.

I know from personal experience the larger the rez, the longer it can take to stabelize. My 30gallons take about a week...

If this is the case for you (which you can verify by leaving it alone for a few days), then you'll need to give your rez a few days before you make adjustments.

Good luck!

 

[Moldy Dreads]

How long have you been growing in this setup for? Sometimes it takes a while for the PH to adjust when you mix in the nutes. Are you mixing well, and testing over a 10 minute time frame, 30 minutes etc..several times? SOmetimes, depending on what I use to PH up or down, it may be a little while before the PH settles. I know that as the plants absorb nutes etc, that can also make PH vary a bit , but from a 5.8 to a 7.4 is quite a leap. In hydro I always chalked it up to medium or nute concentrations. That being said, my plants were usually ok in that 5.5 -7.5 nute range fluctuation, everything else being ideal..

 

[AchromicSkin311]

what type of water are you using before adding nuets and what formula are you using to add in the nuets? And whats your ppm & pH of the water before the nuets?
how long have they been clones? Mine were liking 600ppm while they were under 8"...and the pH would stay 5.9 - 6.2...just my

..also like above...let it adjust for a few days...

my water mix
70% Bottled Water = 5ppm & 7.4pH
30% Tap Water = 285ppm & 7.1pH

I'm Using Lucas Formula for adding nuets
(Target ppm) - (Current ppm) / (Target ppm) * (mL per gal of GH Micro) * (Gals in res)

..i'm still new at this, but this has been working for me...anyone else with more info might help me too!
Ill keep an eye on this thread

 

[bkob89]

Heres everything for ya really quick -

-18 gallon rubbermaid roughneck
-PVC pipe frame with attached mister/sprayers as my watering system.
-200gph water pump
-200w MH
-Watering 15on/15off all day.
-6 Clones

I added 5 gallons of bottled water basically (ozarka 5 gallons). PPM 0, p.h 7.3.
Added cal mag, half dose
Added liquid karma, half dose
Added Pro blend vegetative formula, half dose

Ppm after that was approx 400, where I want it to be. P.h was 6.8, then I lowered it to 5.8. I left to work, come back p.h 7.4, ppm 420. Added water to lower PPM, and ph down, brought it back to 400ppm/5.8ph. Went to sleep, woke up to the same shit, 400+ppm/7.3+ ph...at first I had a water leak and figured due to losing water, ph will rise, but I fixed the leak and still this shit sky rockets way too fast...

 

[bkob89]

Here's an idea:

Fill up your rez and leave it alone for 3 days. Test the ph and ppm every day, but don't add anything.

I know from personal experience the larger the rez, the longer it can take to stabelize. My 30gallons take about a week...

If this is the case for you (which you can verify by leaving it alone for a few days), then you'll need to give your rez a few days before you make adjustments.

Good luck!

Hmm, so make another ress and just set everything before hand then change it out?

 

[Moldy Dreads]

It's the interaction of your chemicals probably.
Just adjust it twice a day and you should be fine. I've had similar issues, and as long as I adjusted it and kept it within the 5.5-7.0ish I managed to have good crops...

 

[Mist]

I always adjust the ph in my resovior BEFORE I add my nutrients. Most hydro nurients have ph buffers that help to keep the adjusted ph in close proximity of where you set it.
But remember that there will be fluxuations in the ph levels that will happen naturally due to the different plant cycles each day meaning that plants will uptake nutrients and ouput waste which will effect the ph levels. And trying to adjust the ph levels several times per day will just stress the plants out from all the acid and base being added all the time.
So I would try adjusting your water and then add nutrients and see where that leaves you after a 24 hour period.

Mist

 

[oldschoolfarmer]

Hmm, so make another ress and just set everything before hand then change it out?

Not necessarily. you could do this, but what I was suggesting is an experiement to see how long it takes for your particular water/nutes to settle and stabelize You can do the experiment, then after it's stabelized add the mixture to your existing rez knowing that the ph/ppm are at stable values.


Just take an 18 gallon container, and fill it with water. Add your 400 ppm nutes and take a ph/EC reading. Leave it alone.

Take a reading the next day and the next day and so forth until the ph stabelizes. It will stabelize given enough time.


Just some advice, YMMV. I learned this trick from another poster here at icmag, and it has served me well.

Good luck!

 

[oldschoolfarmer]

That being said, my plants were usually ok in that 5.5 -7.5 nute range fluctuation, everything else being ideal..

I'd love to see some pictures of flowering plants in the 7.5 range