DWC ...just another pH question

Discussion in 'Hydroponic Growing' started by CannaClay, Jun 21, 2013.

  1. #1 CannaClay, Jun 21, 2013
    Last edited by a moderator: Jun 21, 2013
    I am using GH nutes and the pH has been very very stable the entire grow.  In fact I started adding back water that was about 40ppm(RO from my system) that actually would raise my pH about .1 everyday which was nice b/c I could control the fluctuation.   My plant is easily drinking a gallon of water a day.  I just finished week 8 although this chick is looking like a 10 weeker... 
    About 3 weeks ago it went from 5.8 to 4.8 all of a sudden and I flipped out.  I checked the root zone which looked great and decided to do a short flush since I though it might be to salt build up.
    Now my plant is HUGE. I vegged for 2 months which I am now realizing is too long for one plant under a 400w.  I think my nug size is suffering because the plant is so big and Its only under 400 watts.  Plus I could have trained longer in my scrog and cleared smaller growth better.
    Any how
    day  51 flower  [pH 6.2]
    day 52              [pH 6.0]
    day  53             [pH 5.4] added .6mL pH up back to [pH 6.1]
    day 54              [pH 5.8]
    day 55              [pH 4.6]
    Should I check for root rot?  It would be a pain to lift this HUGE GIRL up with this scrog although I could with my friend. Maybe just flush again...  If I have Pythium/root rot and I put straight RO water in will it still lower the pH?  If straight RO is in there and it doesn't lower PH can I assume it is because of nute intake/salt build up? 
    This GIRL has been drinking over a gallon a day now and I only can fit 5 gallons of nute/water solution in my rez...
    My rez temps have been 68-72 the whole time.
    Any thoughts?  She still looks healthy...

  2. So my pH fell again to 4.6...  I had to look at the roots and they look super healthy!  So I am flushing with PH'ed RO and my pH is stabilizing.
  3. Ph swings happen on occasion, just watch your girl for deficiency signs and react accordingly to those. If you mess around with alot of ph up and ph down you can have a good ph but get some salt build ups that will fuck with your ladies. I only check my ph about twice every rez change (1.5 weeks) once the day after the change and once about a week later. I used to monitor every day and make small adjustments but my ladies looked stressed and a friend told me to lay off of the ph up and down a bit and now they are looking lush and healthy.

    Sent from my SCH-I545 using Grasscity Forum mobile app

  4. ARe you monitoring your solution PPMs at the same time? PH drops would lead me to believe your solution may need to have PPM increased until both stabilize .
    I find PH and PPMs increase in the res over a couple of days if solution is too hot and the opposite if it is too light.
  5. PH fluctuation is normal. most people adjust it every day. as your plant get bigger it will use up the nutrients at a faster rate leading to the solution to fluctuate faster
  6. your plant using more water is leaving you with a condensed solution which naturally has a lower Ph. So whats missing from your question is your TDS
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  7. Only having one container does not help with a stable ph especially with only 5 gallons or so and it being late in its life cycle as well.  A simple help to this situation would be a rez bucket and a float in your grow bucket.  Once i added a rez to my grow it stabilized unbelievably.  it barely fluctuates once i hit the sweet spot.  Good luck.
  8. Ace420 hit the nail on the head.   Right now your plants are using more water than nutrients.  This is normal.   What might help is to get a larger reservoir, or add a fresh water auto top-off.    You can also lower your PPM, to balance the amount of nutrient/water solution, in hopes that the plants will use a more balanced ratio of nutrients and water at the same time.   
    Always top off with water before using pH up/down.
    If an auto top off isn't practical for you, you will need to start topping off manually.   Every day!
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  9. The reason your Ph was more stabile was because you increased the volume of your res which increases your res volume to plant size ratio
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  10. #10 GoldGrower, Jul 7, 2013
    Last edited by a moderator: Jul 7, 2013
    fluctuating PH does not mean your solution is too strong. I have my EC spot on all the time and my PH needs adjusting every day. in fact it has been known to sometimes be too weak with the plants using more nutes than water giving me a constant dropping strength and the PH still fluctuates the same. I change mine from about 6.5 to about 5.5 every day. now and then I skip a day if I'm busy, when this happens they are still about 6.5 so this must be their natural balanced state given my set up
  11. Well Ive set my grow up a few different ways now and the latest has been the most stable.  The set up I had before tended to be less stable and that was a 3 bucket system with one bucket being the rez (center bucket)  A few evolutions later I use a cooler for my single plant and a rez in an adjacent room that auto top offs.  Ive had better results with the auto top off rather than just one large system.
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  12. I think you may have misunderstood :) Dropping pH happens with a more dense solution (not fluctuating). Your Ph needs adjusting every day because your plants are using more nutrient than water creating an imbalance in ions (hydrogen vs hydroxide) which leads to raising pH. 6.5 tends to be where the plants stop as this is the top of the pH range where the elements the plants need can be readily uptaken. If you leave the plants for a few days, they will eventually take up enough water, leaving a denser solution, which will lower pH(assuming your nutes have ANY buffer in them that alter pH). hope this helps :D
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    Yo Gold!  A pH fluctuation as you describe means that your plants are using up more nutrients than water.  If you swing from 5.5 to 6.5 each day, that means you can bump up your PPM safely, and a larger reservoir would be helpful, too. 
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  14. what if your ph is dropping fast instead of rising.  Say you adjust to 5.8.  4 hrs later it's 5.2.  you adjust to 5.8 and 4 hrs later it's 5.3.  You adjust, and 4 hours later 5.4? ppm is stable at 550.
  15. this isn't true, this PH fluctuation is the same even when the solution is too high. it more to do with what I use to lower the PH amongst other things, but the strength of the solution has nothing to do with it. proven by the fact that some times my solution can get too strong and sometimes too weak and still have the same fluctuation of PH
  16. this is often a sign of organic decay. Check your roots and res temp. repsond accordingly
  17. what if you can't check your roots because of the scrog and rez temps are steady at 64-69?
  18.  design your next grow with the ability to check roots.
    Double check your temps with other sources that can be verified/calibrated
    Increase aeration if possible
    are you watering at night? (you shouldnt, if you are)
    Are you sure youre getting an accurate TDS reading and that youre not just suckking up a LOT of water? I dont really know all about your system. Feel free to describe it in detail and Ill try to help :D
  19. Lets say in a system with 2 x 5 gal black pails(holding a total of 6 gal) connected together.  A small recirculating pump moving the nutrients around.  Air-rated by a http://www.petsmart.com/product/index.jsp?productId=2753029&f=PAD%2FpsNotAvailInCA%2FNo  Using AN.  1 Plant with PPM around 570.  Verified by a Nutradip trimeter (calibrated weekly but in fairness not the temp setting but water is cool to the touch).
    What about nutrients that have been frozen?  If a grow was done using frozen nutes that were a little over 1 year old?  Say also the plant was showing signs of a mag/cal def.  Maybe worth trying a full 24 hr flush then using brand new Sensi grow ph perfect nutes?
  20. increasing aeration would be simple.  just add in the spare pump. 

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