[@BobbyDigital quote=“Bobbydigital, post:5, topic:43076”]
Careful with that chart with the ppms. It is a 700 scale chart so if your meter is a 500 scale and you put that amount of ppms in, you’ll burn the plant. I adjusted this to 500 scale.
[/quote]
I am asking this through @Metallicide thread because I think it will have general application to other beginners like me. This what THCFarmer said " What’s the difference? The ppm 700 scale is based on measuring the KCl or potassium chloride content of a solution. The PPM 500 is based on measuring the NaCl or sodium chloride content of a solution and is also referred to as TDS - total dissolved solids.
The pen I have says it calculates PPM as follows:
This advanced digital ppm meter pen with Advanced Microprocessor Technology, combines TDS Meter (Total Dissolved Solids), EC Meter (Electrical Conductivity) …
Questions
- does this mean I have a 500 ie. pen that uses sodium chloride to measure TDS converted to PPM? (it is a honeforest-white pen)
- Fox Farm nutrient schedules need to be adjusted from 700 to 500 scale.
- You are not saying to reduce FF trio application rates but rather
- If you are dosing based on PPM and the plant’s growth stage (say 1400 for mid-late flower) I am actually looking for reading on my pen of approx 5/7 -70% or about 1000 ppm
Now my head hurts! Is this what you were saying?
I just mixed 2 gallons for week 12 feeding. I’m actually mid week 15 and 2 away from harvest. MY ppm is only 680?
1 Like
You can tell what your meter is by testing your Ppm then switching to EC. If you’re going in at 680ppm and switch to EC and it reads close to 1.4, your meter reads on 500 scale. If the EC is closer to .9 or 1.0 then it’s 700 scale.
Basically the 500 scale means every 500ppm is 1ec. So 1000ppm = 2ec. 700 scale means 700 ppm = 1ec. So 1400ppm = 2ec. Here is a chart 500 scale (Hanna) on left and 700 scale (truncheon) on the right.
Now you can see where fox farms calls for 2100ppm in week 4 of flower. But that’s on 700 scale. It’s only 1500ppm on the 500 scale. If your meter is 500 scale and you adjust the feed to 2100, you’re going to nuke the plant. I hope this makes sense.
2 Likes
In other words, the pen’s reading is absolute. If my pen reads 1000 it is still 1000. I understand what you are saying bout FF. I am just never near what it recommends during the first weeks because of the soil I use. I’ll save the above table. Thanks for getting back to me.
1 Like
Right now I’m trying that @BobbyDigital and my ppm is 168 and when I switch to ec it says 337. That’s just my plain well water. Which scale would that be?
Yes and no. 1000ppm on 500 scale does not equal 1000ppm on 700 scale. So it’s important to know which scale your meter is on and also what scale your feeding chart is on.
Yours is on 500 scale. You move the decimal point 3 spots to left on ec. So it’s .337 ec
1 Like
Thanks man. That clears up a ton. I haven’t been give the plants any N either and noticing the others that are early flower are getting lighter colored and splotchy. I should be able to avoid the problem in the future now. Lesson learned on following directions much more closely. I did a foliar with cap mag and tiger bloom and when the soil dries i will flush and get nutes right and ppm up.
For the foliar do i do it everyday? Mixed into a 1L sprayer and of course it doesn’t take much to soak the plant so wasn’t sure if it absorbs more directly in foliar so doesn’t need to be as strong?
I don’t foliar spray in flower
1 Like
I was PSYOP. SOCOM. Though Army, I deployed with Marine Infantry. I earned a CAB and a CAR (combat action ribbon, mariness). A former Ranger was on our PSYOP team. He had the EIB, and the CIB, and a CAR. He explained it like this, EIB meant he always knew what to do. CIB just meant he happened to be somewhere in the vicinity of combat action, and CAR is for effectively returning fire, not just taking fire. He would only wear the EIB, but he also wore a battalion ranger scroll on his right sleeve(except when deployed we didn’t wear army uniforms very often while in Helmand, we wore marine frogs without any patches.) It’s interesting to hear everyone’s take. Thanks
1 Like
Yeah I know quite a few guys who got their CIB for being in the general area. I think it should be direct fire but that isn’t up to me!
2 Likes
A lot of guys are lucky to have never seen fire. Somedays I wish I would have been one of them.
2 Likes
Since starting to foliar it seems better. Its almost dry so I’m going to flush it hard and then finish with nutrients to get it about 1400 following the chart.
