Millwaukee PH meter and PH Liquid- Conflicting readings

Discussion in 'Hydroponic Growing' started by datt420, Jan 4, 2013.

  1. So i'm going about adjusting my pH as usual, and enjoying my new continuous ph meter, having used the liquid since I started growing, and i notice that my 1 gal res just wont go down from about 6.8, going down .1 or.2 every 1ml of ph down I add. Usually, 2 or 3 drops puts it way too low. So i'm wondering whats up, and I check with the ph liquid. Sure enough, its red, way too low. So i figure my meter must be off calibration. I take out my 4.01 reference solution, and it reads out at 4.1, not much off at all.

    So which should I trust, the meter, or the liquid?

    I guess if the liquid is wrong, ive had my ph too high this whole time, not that its had much of an effect.

    If the meter is wrong, that's a shit meter for 70 bucks. I love my Milwaukee drill, i figured it was a good meter as well.
     
  2. I would trust the liquid over the meter, because it's a tried and true chemical reaction. The only way you can screw that up is by using too little/much liquid for a too big/little sample size.

    I'm not sure on the Milwaukees, but my Hanna needs to be calibrated at both the 4.01 and the 7.01 Ph scales. That might be part of your problem. Is it one of those cheapie yellow pens? I've found that particular one to be mostly a heaping pile.
     

  3. Na its not a pen, its a box unit you can mount on the wall with one of those gel probes. And I did calibrate it with both, it reads 7.0 at 7.1 and 4.0 at 4.1.

    It was the same price as a similar Hanna, i just like that brand.
     
  4. It sounds like you need a 3rd reading from a different device.
     

  5. If only I had one. For now, I guess im going to trust the $70 meter over the $7 liquid, unless the plants start showing signs of it being off.
     
  6. You could bring your water into one of those pool stores and have them test the PH. Tell them it was from your pond. Free water analysis at Lesley's pools. I know that much is true.
     

  7. Word, thanks for the heads up
     
  8. Let us know what happens
     
  9. Again, I highly suggest trusting your liquid over your meter. The liquid reacts the same exact way to your test subject, everytime. The meter has multiple points at which it can fail on you.

    The price differential doesn't mean anything. Just because the meter is ten times more expensive doesn't mean its going to be more accurate.
     
  10. ^counter point; the liquid could have been mishandled. Temp fluctuations and old solution could give you mis reads.
     
  11. While that is certainly true, I don't believe this to be the case. While the Milwaukee probably does have ATC, unless extreme, temperature changes with the liquid won't affect the results by all that much. Certainly not as much of a difference as to result in the discrepancies seen by the OP.

    Maybe it's because I've gone through my fair share of pH equipment in my time; whenever anything comes up that doesn't make sense, it's almost always the meter being the source of the headaches.
     
  12. KK, let me hijack this thread for a moment. I'm flushing with humboldt honey molasses for the first time. Started with RO water and figured I'd run this molasses until I harvest. Well...my PH is floating up 1-1.4 pts/day. I'm throwing PH down to keep the solution in my res at a correct PH but I really hate owing this...

    Have you had any issues with molasses affecting your PH like this?
     
  13. Plain RO water has almost no buffering capacity, so that is probably what you are seeing happen. The molasses does have some buffering capacities to it, but still nowhere near what your normal nutrient soup has.
     
  14. I was thinking that the molasses was breaking down and causing the jumps. Combined with the RO it's a killer combo. I think the extra sugar in the molasses is giving me a ton of crystals. I'm stoked with the results but hate adding all this acid to correct the PH.
     
  15. It will lower your pH after you initially introduce it into your water, but it shouldn't effect it much past that (at least not in any degree that's different from the norm).
     

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