Anything is better than nothing my man. BlueLabs is definitely the cream of the crop (I use their products). That said there is another brand you should consider called “Hanna”, they are a bit less expensive and are just as reputable. Check out their combo device here:
https://growgen.pro/hanna-instruments-replacement-probe-for-hi9026-21996.html
Exactly that Hanna meter is the one I use very happy with it
9/10 times those cheap meters just need new batteries, and sometimes a calibration. The ones that can’t be calibrated sometimes work out but since I got one that can be calibrated it’s been much more accurate.
The way to tell if it needs a new battery or not is to put it in some plain water for 5-10 mins. If the number keeps going down slowly (like -0.1 every 20-30 sec) then the battery is too weak and the value it’s showing is wrong to begin with. I’ve found if it’s in that state and it’s used for an hour or two it’ll give very incorrect readings during that time.
Interesting, I never knew the accuracy is dependent on the battery power.
I went through 3 of them when I couldn’t seem to get a steady number for more than a week or two. It worked great at first but quickly degraded.
When the 2nd one died I replaced the batteries and then it worked again, and in testing those batteries in the other one found it also worked properly again.
I later picked up (another cheap) one with a calibrate button and that one reduced the margin of error I was seeing with the other 2.
I would have just stuck to the drip tests after going though all that, my faith in electronics would have been lost, and I work as an engineer 
Getting quality batteries was the real trick I think. The better meters just have more circuitry to not give a wrong reading (they’ll flash a battery indicator and show ERR/BATT or something fancy). The cheap ones just skipped that step (among others I’d imagine), which is part of how they are so cheap.
It’s better than nothing (in my opinion) and not as hard on wallet. If I didn’t have the grobo monitoring the pH then I would definitely invest in better pH monitoring equipment, but found a way to make these work for my purpose.
I do plan on getting the PH meter by Bluelabs, I wanted to wait a bit longer until I learned a bit more about growing and feel confident enough to run a successful grow tent. I’ll grab one as part of the expansion.
I ended up with these and installed it with the new grobo that arrived and its been working great so far however I am unsure if the ppm is actually that high or not since I am in late veg but for now I can at least see if she is eating on a daily basis and get ph in real time.
Is that ppm500 or ppm700?
I believe its the ppm700 range i am not sure how to find out but manual says the range is 700 to 1900 ppm
These are the specs on it:
http://www.milwaukee-instruments.com/MC410.html
Just saw the label, it’s a TDS meter, almost certainly PPM500.
good to know, thanks
The instruction manual says its a 0.7 conversion, wouldn’t that make it the 700? They have a MC410A model thats a 0.5 conversion. Not sure what that really means but I’m just trying to connect dots lol
Well in that case I will make my point haha. My PPM 700 reading has been anywhere from 1400-1700 throughout most of my grow. I did utilize some additives however I believe that Grobo recipes (or at least the one I’m running) dose a very high amount of nutrients & cal-mag.
I am sure this is the 700 scale and my pen is on the 500. I just did this conversion and its accurate to what im reading so my ppm is actually OK
You are on 2nd half of flowering from what I have been following. This chart i have says 1000-1600 ppm is the range you want. Your 1700ppm converted to the 500 scale is 1214. It looks like you are in range if this conversion process is correct.
Also comparing to this fox farm feeding chart, which looks like its using the ppm700 scale, i think both of us should be in range. Shes been going pretty well with minor signs of burns but i think that was from the first late veg dosage. Shes been fine after 2 top offs
Interesting, all else I’ve seen throughout the online research I’ve conducted on educational sites and forums indicate that these levels are quite high. My plant was perfectly healthy throughout the veg. phases however it did experience wide spread burning (managed to keep it contained to just the leaf tips) once it entered transition.
yeah im guessing its the transitions, change of dosage may cause some tip burning. I am planning on adding 2 additional cups of water to dilute the solution in the res during my next transition and skip the first daily top off, since the grobo just dumps the nutes needed in the high range, instead of ramping it up week by week.
Like when I first started late veg, the grobo dropped in 650ppm (500 scale) into the reservoir, while it should have been 450-700. So there isnt any ramp up, just a steep incline of nutes. So this is what I’m thinking is causing the nute burns. Your case may be different but I’m thinking this may be pretty common, especially for anyone whos adding additional nutes.
I also read that europe uses ppm700 scale while north america uses ppm500 scale so this sort of making sense to me.Referenced from bluelabs
Very good points you raise, going to try something a little different with my next grow.
