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Thread: Why is PH falling in DWC??

  1. #21

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    Thanks for the vote of confidency guys.
    I have started to write a thread but have limited time just now. I hope to get it sorted next week.

    I think it can be very confusing what to do when you have what appears to be nutrient burn, the automatic response is to lower the EC. However, generally, this just makes things worse.

    The key to understanding what is happening is the water levels as I mentioned. If they are more or less static when into flower, something is wrong. The issue then becomes what to do about it?
    Increase or decrease EC?

    Once you understand how plants roots work, the answer is obvious.
    They work in a very similar way to an R/O machine. So nutrition will flow from the higher EC to the lower EC in a reverse osmosis process.
    Which means, if your EC is climbing, you need to increase EC to a level that stops it rising.
    If you have hard water over 0.4, it may mean feeding with an EC as high as 1.8-2.0. This is something I wouldnt normally advise in DWC.

    However, if you keep in your mind that a "normal" EC of 1.2 usually brings decent results in DWC, this should be the nutrient level on top of background EC.

    With both guys who have had issues who contributed to this thread having high background EC's, I think this is the source of the problems. So being brave will pay dividends.

    Remember, the key to this is what is happening to the water levels.
    Good luck guys.
    W
    Any suggestions are opinion only. I get some right, I get some wrong but I always try to help.

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  3. #22

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    Quote Originally Posted by Woody J View Post
    *This is assuming the water level is remaining more or less the same*

    A falling ph with a rising EC is not the time to start adding just water.
    I will explain why.
    Your plants roots sort of have their own internal EC, which will be different from that of the water/nute solution.
    So if the plants internal EC is LOWER than the solutions, the plant will absorb nutrients along with water.
    If the plants roots however have a higher EC than the nute solution, they will leech nutrients and raise your nute EC.

    So, if you have a static water level, with a rising EC, raise your nute EC.

    If your water level is dropping and the EC is rising, this is when you need to add water to the nute solution.

    This has not looked at the ph.

    If your ph is falling in DWC, it generally means your EC is too low (as above).

    There is a complication however and that is your air quality.
    When pumping air into a DWC bucket, you are pumping in Oxygen but also CO2. The addition of CO2 to water in this way is exactly the same process responsible for acid rain. (Power stations pumping CO2 into the air, which goes into clouds and hey presto, acid rain".

    So, if you are in a city, with high levels of CO2, this may be the cause of falling ph.
    A res change, maybe even twice usually sorts this out.

    So, the solution to this depends on your water levels.
    W
    i know this is an old thread but who cares ... this information just saved my grow ( 4x automazar in rdwc modded wilmas) thanks woody

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  5. #23

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    Temperature variations play a big role in PH , water warms up , it gets sweeter (alkaline) colder more acidic , so if yoou are having temperature fluctuations in your room , that could the culprit my friend

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  7. #24

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    think my levels are right now?

    water level dropping
    ec 1.2 staying where it is
    ph 5.8 staying where it is

    are these conditions ok?

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  9. #25

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    Default Dwc

    First time poster long time outdoor growing first indoor 3000w kingsled in dwc

    I know this is a really old post but thanks without the information I feel I would have killed my plant's but the thing is I upped my EC to 1.4, I was under feeding first time dwc and I burned them eirly on, they are looking great and for a couple of days fine but now it is doing the same ph dropping and EC increasing down by about .4 a day and ppm up about 1000 or ec about 1.7 so my question is should I increase my EC/ppm to that level or just under or just over? They are drinking heaps just over a L a day and have been topping up with EC 1.4 and a pH of around 6.2 to bring my pots up to about 5.9

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  11. #26

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    Quote Originally Posted by Hippyhighs View Post
    First time poster long time outdoor growing first indoor 3000w kingsled in dwc

    I know this is a really old post but thanks without the information I feel I would have killed my plant's but the thing is I upped my EC to 1.4, I was under feeding first time dwc and I burned them eirly on, they are looking great and for a couple of days fine but now it is doing the same ph dropping and EC increasing down by about .4 a day and ppm up about 1000 or ec about 1.7 so my question is should I increase my EC/ppm to that level or just under or just over? They are drinking heaps just over a L a day and have been topping up with EC 1.4 and a pH of around 6.2 to bring my pots up to about 5.9
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  13. #27

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    That should help...

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  15. #28

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    @Woody J
    Great info woody. I agree with everything you have said but i dont see any consideration to water quality.

    Municipal water with modern chlorine or chloromine which will not evaporate will affect the nute bindings on most bottled nutes.

    Aerating this type of water will raise the PH. I have seen this many times but have not found a good explanation.

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