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Is Phing Flush Actually Even Possible?

Discussion in 'Advanced Techniques & Problems' started by bibbles, Feb 1, 2019.

  1. I've got a Hanna combo meter, and I can't seem to pH RO, or the light feeding some recommend. I can get the pH down to 5.9, but within five to ten minutes it'll be back up at 6.3, without fail. I could probably dump an entire bottle of pH down and still be above 6 within a few minutes, what the fuck is going on? I assume the rest of you don't spend hours and hours pHing your flush, right?

    I'm starting to suspect that this isn't a real thing, just a lie used to get people to give up on growing. :/

    EDIT: The meter is fine when it comes to normal solutions, this behavior has persisted through two meters, and multiple probe replacements.

    EDIT: 5.7-6.3 in about 15 minutes again. What the fuck.
    Last edited: Feb 1, 2019
  2. Oh, and yes, I've tried adding pH up or down to buffer, then using the opposite to adjust. No dice, nothing. Is there some special ph up/down you use during flush?
  3. You need to measure and adjust your Alkaline first, then PH. My guess is that’s what’s causing it
    JWM2 likes this.
  4. The alkalinity of my RO? Wat.

    I just increased my base until the pH remained stable.
  5. Kot


    What is he main ingredient in your Ph down? I can make any water to PH 2 if I wanted with mine, which is phosphoric acid.
    UncleRomulus likes this.
  6. Ro water has no alkalinity so it will change ph very easily.

    Bubbling with an air stone will raise it.

    Just the air around it can effect.

    No alkalinity no stability or buffer.

    But when you add nutrients it should stabilize. Cal mag is designed specifically for this.
    New school, Dirtbag, bibbles and 2 others like this.
  7. Lol, we're on the same page, I was thinking "RO has no alkalinity".

    I'm at ~200ppm, but my tap is 550 so I've never really had a basis for "normal" I suppose, just ultra hard, and RO.
  8. Haha, the just add calmag adage is right for once.
    bibbles and MIMedGrower like this.
  9. you are never supposed to put a ph meter into strait RO water btw. From Bluelab:

    lol yep exactly. Read da manuals.

    Also you should never flush with strait RO water.
  10. I’ve been balancing my straight water without any chemicals by using tap water and filtered through a cheap filter jug water. The filter is mildly worn out so it drops ph down to 5.7. My tap is 7.5ish. I can eyebawl it within .1-2 lol
  11. PharmHand


    How long are you mixing your solution for? My ph will rise at least a few points in the first 5-15 mins of mixing- like someone above mentioned it has to do w oxygen saturation. If ya mix it up in a room w high co2 it will do the opposite, drift down. Mine goes up but then plateaus at o2 saturation. I’ve got a big holding tank for straight water (40ppm), when I initially fill it the ph sits at 5.3-5.5. If I turn on the air stones overnight it’s sitting at 6.4-6.7. It appears the lower the solution concentration the more it’s affected by the added oxygen. The lower the ec the longer it takes to adjust ph too I find. I use ph paper a lot during flush it seems to give a faster more accurate reading than even high quality ph meters. These are my observations, it’s never been an issue for me so I’ve never looked into it too thoroughly. Maybe someone can shed some more light on the specifics?
    bibbles likes this.
  12. From Hanna
    Screen Shot 2019-02-06 at 1.17.24 AM.png
    RO, DI, or distilled...
    Screen Shot 2019-02-06 at 1.38.06 AM.png
    All the god damn time! lol

    It was ~125ppm, not RO, just needed a bit more to stabilize.

    I believe I generally let the RO bubble for 10-15 minutes before mixing (and it will have sat out previously, albeit loosely covered), but the fact that I've cut CO2, and reduced the number of things added, especially in terms of salts which need time to dissolve, thus the time has likely dropped as well... good things to think about. I had considered strips or drops as an alternative, but after reviewing some things I realized I just needed to adjust my perspective. "Hard water" is just below 200ppm, my light feeds were just a bit too light.
    Last edited: Feb 6, 2019
    cemchris likes this.
  13. PharmHand


    Just a quick rinse in ro or distilled to prevent contamination of the buffers- I do that too then shake it off when calibrating and just before it goes into the KCl storage solution after use. RO or super low ppm water is very reactive/corrosive and will deteriorate the probe rapidly. It has to do with the way the probe actually works- every measurement taken takes a little life outta the probe; ro / low ppm does it at an accelerated rate. I flush w 40ppm, no issues adjusting ph, it just takes time and very small amounts of up or down
    cemchris likes this.
  14. I run the cheap Bluelab pens and they last me a couple years usually each time. I usually just replace them cause it feels about time. Only thing that broke on me was a Truncheon after like 7 years (granted its just a general meter). Never rinse. Never use the storage solution. Never put them in RO water. Just calibrate once every 2 weeks and go. I use them everyday. Don't know but going through multi meters and multi probes I prob would never buy that brand ever again specially if we are talking that many over a 2 to 3 year period if they were all Hanna.

    All I was suggesting is ditch the Hanna. Sorry should have said that in the other post. I have had other buddies have nothing but problems with the Hannas over the years.

    The other thing is you should let ph buffers chill for a while before taking measurements. I know using the AN down when I mix strait salts I need to usually wait at least 20-30 mins to really get an accurate reading where it isn't drifting anymore. This is without all the PH buffers in bottled nutes. PH Up is even longer.
    1diesel1 and PharmHand like this.
  15. PharmHand


    You store the probe dry? Think it says in my bluelab manual “ if it dries it dies” lol. I used pretty much every brand ph meters over the years..... Hanna, bluelab, trimeter, hm, Milwaukee, nutridip. I never had much luck w the bluelabs but I didn’t used to be so kind to them I suppose. These days I like the nutridip trimeter ones they’ve been rock solid for me. I check/calibrate them one a month but they don’t budge. I use the bluelab kcl The probes stay accurate forever but I’ll switch em out every 9-10months for good measure, the probes 50$- I don’t mind
    cemchris likes this.
  16. No I use the cap that comes with it and the sponge is usually wet from when I dip it in. I never worried about KCL or storage solution because they are used everyday. My meters will never be off more then .1 when I calibrate if any. I usually just get a new one for my own peace of mind and since they are pretty cheap. I ran the combos/guardians in the past and also have nothing but good things to say about them except the ph probes are all glass so if you are hard on the meters you will prob end up replacing the probe once or twice after you break them.
    Last edited: Feb 7, 2019
    1diesel1 and PharmHand like this.
  17. The second meter was a warranty replacement, and I replace the electrode once a year or so. The junction clogs over time and I'd rather swap it a little early than be caught off guard when it fails.
  18. Ikkt


    Im not that cheap and nowhere near "green", but reading this strikes a nerve.
    There's no need to throw perfectly good electrodes away!
    They're simply cleaned with 0.1mol HCl solution, or HCl solution with Pepsin if you often measured high protein solutions. (You can get pepsin in a Pharmacy) That works several times when it won't stay calibrated anymore for more then a couple weeks. Does nobody read fking manuals anymore?

    I use the same Greisinger electrode daily since almost ten years. It dried out several times and even fell completely dry. Change/refill new reference solution and it should hold its calibration for months to years again. I learned to trust a calibrated quality electrode more than I trust bottled calibration solution.
    And i've learned there's no need to calibrate unless something seems odd. And till now my pH meter was never off more than 0.1, it's always been something else. Good electrodes are made for harsh conditions and lab use. What we do with em in many years is less than what they have to take in a couple weeks lab use!

    If your water has no or nearly no buffering capacity pHing it is quite useless. If you test your runoff with RO water or very low ppm water and your "soil" doesn't absolutely suck there can be no relevant difference. Except perhaps the first few millimeters of "Soil", but who gives a f?

    PharmHand likes this.
  19. PharmHand


    The difference is we’re using what are likely
    very cheap meters compared to your lab quality ones. The manuals of ph meters aimed at dope growers give u no directions for restoring your probe, they just want u to buy a replacement. What’s even more confusing is the difference between what manufacturers recommend for their equipment. Hanna says to never touch the actual probe doing so could ruin it. Bluelab sells a cleaning kit that includes a tooth brush to scrub the probe. Hanna says to store the probe in KCl, bluelab says u can store it in ph4 solution. It’s a little confusing. Over time I notice the probes take a little longer to give a stable reading but eventually give the correct readout. The new probes react instantly. What’s one of your lab grade units cost?
  20. Dirtbag


    Lol man, some of these threads kill me. I was going to reply but by the time I got to the bottom I forgot what the damn thread was about haha.

    You cant ph RO. There is no ions or cations in it. No ions or cations=no potential hydrogen to measure.

    There is also no need to if you are using a soiless mix. Peat is not inert like rockwool, it has a cation exchange capacity and so it holds nutrients. As soon as you water it with RO, the water will take on the nutrients and then buffer to whatever the ph of the soil is. I always use either straight RO or rainwater for my last 2 weeks of bloom and have never had an issue, just delicious clean burning buds.

    As for the ph meter. A rinse is fine with RO, just dont store it in there. The osmotic pressure will draw the KCL out of the probe bulb and cause it to read slow. Store it in KCL storage solution or ph4 buffer solution.
    MIMedGrower likes this.