SUPER informative guys!!! I've been having a pH issue I'm hopeful you scholars can help me solve! I have the Blue Labs pH pen.
View attachment 367633
When I bought it, I got two so I'd have a back-up. I've been using only one of them for about 9 months now. I've been having pH problems which have worsened over the last 2 months or so. The problems are most apparent in early veg. The plants become stunted and get what I had thought was burn (but no feedings have been given at all, and I'm using straight Happy Frog soil -- shouldn't burn). Here's an example of what I'm seeing...
View attachment 367627
View attachment 367628 View attachment 367629
I cleaned my probe with the Bluelabs probe cleaner and recalibrated. Then I put the meter in the 7.0 solution, it goes right to the "7" number. When I rinse and put it in the 4.0 solution, it goes right to 4.0! I calibrate and get a check mark indicating a successful calibration.
SO...I hydrated and calibrated my back-up unit thinking it was time to put it into service. Well..it seemed to take a long time for the meter to get to the 7.0 number. Then, after rinsing and placing into the 4.0 solution, the meter never did get all the way to 4.0. It only got to around 4.5-ish, and it took forever for it to get there! I hit "CAL" and again got a check mark indicating a successful calibration.
My problem is that the two meters now read differently and I'm not sure which to trust! The "old" meter still settles in on a number pretty fast, while the newer back-up meter is still taking a long, long time to get settled on a number. In fact, the auto shut off hits several times usually before it's done. The readings are several points apart with the newer back-up meter reading a higher pH in any solution. Example: When the old meter is reading 6.5, the newer back-up meter will be reading 6.7-9.
Common sense is telling me since I've been having unexplained pH problems (I've been suspecting my soil up til now) I should start using the newer back-up meter which is reading higher. However...something in my gut is telling me not too. It may just be my lack of confidence due to it's slow reading and difficulty calibrating.
I would really appreciate some of you all-knowing pH gurus lending me your advice! Would you trust the new meter or stay with the old? Do my problems in the pics look like they might be caused by higher pH or a lower pH? This would help me in deciding too.
Thanks so much in advance!
Its not a burn but rather a deficiency. If it was a toxicity you would see burnt leaf tips.
Ca will have the brown spots intervienly not JUST on the perimeter.
Keep in mind every time you put that probe into your nutes some of those nutes will transfer up into the reference solution, if you ever have seen the clear probes you can see this happening.
I would not worry quite yet. 0.2 is not a big difference considering that you have been using it longer I would not worry about it. MAKE sure you calibrate your probe and make sure to check it before everytime you use. it. Basicly you need to calibrate it every 30 uses. so you check your water 10 times a day then every three days you need to calibrate.