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is ph drop normal in hydro the longer it sits

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    HYDRO is ph drop normal in hydro the longer it sits

    so i have bubbleponics hydro setup with 3 five gallon buckets with a five gallon bucket reservoir with water pump going to top of each bucket and air stones inside each bucket , with general hydro trio for nutes, and hydroguard and mixing with straight city water. so when mixing my water change ill drain my system completely . ill fill a five gal bucket with water , has a ph of 7.5 and ill add my trio and guard and ph is now 6.5 . so ill add about 7ml /5 gal of gh ph down with a final ph of around 6.

    my question is this. the next day ill check my ph and its dropping now below 6 and after a couple of days its pushing a ph of 5 and dropping . i get scared and add some tap water to raise the ph . my understanding 5.5/6.5 for ph is target.

    is this drop normal as nutes are used out of solution ?
    is it safe to let drop below a ph of 5?
    is it ok to bring the ph back up to range with tap water?

    everytime i change my water ill vary the amount of ph down ,sometimes more sometimes less cause i know you want to hit the entire range of 5.5/6.5 , i also know you dont want to use ph up or down the same time , but is it ok to go back up after usingh ph down with tap water?

    I'm using a bubbleponics system as well and also a very new grower myself but my understanding is that it's normal for pH to change and you need to check it often. As water and nutrients are absorbed by the plants the pH and the TDS ppm in your solution will change. You want to keep it in the 5.5-6.5 range even if you need to adjust it daily. The pH can also affect how your plants absorb nutrients. See the attached chart.

    Click image for larger version

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    The change in pH can also give you information about what's going on with your grow. Here's a chart I found that shows what the water, pH and TDS changes indicate.

    Click image for larger version

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    Attached Files


    • justinelam1973
      justinelam1973 commented
      Editing a comment
      thanks for the response and graphs Dannyboy58 . what are they refering to as (ec) on the middle graph

    In the image you can see EC on one side of the indicator lights on the truncheon and ppm on the other side. And EC refers electrical conductivity.
    Last edited by Poppa; 06-08-2021, 09:31 PM. Reason: I'm HIGH


      I don't use EC or an EC meter. I use a TDS meter to mange the nutrient level in my system. I'm not certain but I believe EC is more important to soil growers to measure in their runoff?


        EC (electrical conductivity as poppa said) is supposed to be more accurate than TDS (total dissolved solids), but with that said I read somewhere that many of the measuring devices that say they measure both actually just measure in one way and then apply a formula to calculate the other rather than having sensors for both (can’t remember which one was used to calculate the other).

        With regards to whether pH lower than 5.5 will harm the plant.... to my eternal shame I ignored calibrating my pH meter and when I did finally get around to it I realized my water was actually closer to or below 5.0 on a regular basis. The plants still appeared normal looking but I had a higher than normal incidence of hermies. This went back to normal for the subsequent grows once I started calibrating. I was sure it was these CBD seeds I have that were causing the hermies (usually grow one CBD plant in each crop) but I think I was unfairly maligning them when my lack of calibration was the true culprit. SoOrbudgal - you once asked me about the cbd strain I use and I’m not sure if I told you I no longer think they were my problem. They are called CBD Jam, I think from Delicious Seeds.


          thank you all who took the time to read and give me some input


            so far so good even with ph drops . this was skunk#1 from seedsman , this plant just grew amazing in bubbleponics


              Nice! Skunk #1 is hard to screw up and yields like a champ. I noticed in my RDWC hydro a few grows ago that I had to keep adding pH Up to keep it from getting too acidic. I figured out that the plants (which were flowering) were consuming the potassium from the pH Up and driving the pH right back down. I started using some stuff called PeaK which is a balanced supplement with extra phosphorus (P - acidic) and potassium (K - basic) along with the regular flowering nutes and didn't see so much fluctuation after.
              Project Murcott:
              6 bucket RDWC in 4x4 tent, Platinum LED P4-XML2. Six male/female Crockett's Tangies plus another in coco for seed and a fem Kosher Kush in coco for a 24K Gold F1 cross.

              Project Deuxberry:
              3x3 tent, Platinum P300 LED. Five Dutch Passion Blueberries in coco for seed.

              Aurora Soul nutrients - Grow, Bloom, Infinity, Big Swell & PeaK.

              Side project in coco: Pink Kush CBD, CBDV 1:1, Dark Devil and Northern Lights autos in new 4x4 tent under new Platinum P4-XML2 LED.

              32"x32" tent with T-5 fluorescent panel. GSC, Lavender and PPD seedlings with more to come.

              On deck: Mother's Finest (Sensi), Golden Tiger (Ace) plus assorted feminized seeds. Have over 1000 homegrown Ghost Train Haze seeds and hundreds of Skunk #1 available for trade.


              • justinelam1973
                justinelam1973 commented
                Editing a comment
                thanks for the feedback , thats interesting. im thinking maybe adjust my mixing amounts like you and see if it works . thanks again

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