Total Newb Question about PH and PPM meters


First of all, would like to say, this is my first post in the forums. I am a completely new grower and have never grown anything. I live in MA, and we have recently approved recreational marijuana use, which includes growing. I have been watching a ton of videos on YouTube and reading through forums and grow journals. I also have some friends and family that started growing a while back, which peaked my interest even further. I have decided to go with DWC for my first grow. I hope I’m not being overly ambitious, but I wanted to go with a grow style that someone I know is using so I can talk to someone directly when questions arise.

Now, to get on with my question! I wanted to find out if my tap water would be in a reasonable range to grow with. I dont have much money to start this up, and I’m trying to save as much as I can, with everything. I purchased a $10-$15 PPM meter and PH meter combo online, and they should be arriving shortly. Neither meter came with a calibration solution, and what I need to know is, can I trust these tools to be correctly calibrated out of the box? I just want to check the PPM and PH of my tap water, but need to know if I have to go out and spend more money on the solutions, or if I can just use them?


Likely not youd be better getting a calibration fluid and calibrating it as soon as opened before first use that way you know your reading is accurate and avoid any crucial mistakes off the get go.

Also welcome to ilgm @xDeeTeRx you’ll find lots of valuable help here we are happy to have you here



This will help you to better understand PPM
COPY AND PASTE This info to your file for future referance.

PPM–EC conversion Chart

Re-printed with Permission from Jorge Cervantes;

EC Hanna Eutech Truncheon CF
ms/cm 0.5 ppm 0.64 ppm 0.70 ppm 0
0.1 50 ppm 64 ppm 70 ppm 1
0.2 100 ppm 128 ppm 140 ppm 2
0.3 150 ppm 192 ppm 210 ppm 3
0.4 200 ppm 256 ppm 280 ppm 4
0.5 250 ppm 320 ppm 350 ppm 5
0.6 300 ppm 384 ppm 420 ppm 6
0.7 350 ppm 448 ppm 490 ppm 7
0.8 400 ppm 512 ppm 560 ppm 8
0.9 450 ppm 576 ppm 630 ppm 9
1.0 500 ppm 640 ppm 700 ppm 10
1.1 550 ppm 704 ppm 770 ppm 11
1.2 600 ppm 768 ppm 840 ppm 12
1.3 650 ppm 832 ppm 910 ppm 13
1.4 700 ppm 896 ppm 980 ppm 14
1.5 750 ppm 960 ppm 1050 ppm 15
1.6 800 ppm 1024 ppm 1120 ppm 16
1.7 850 ppm 1088 ppm 1190 ppm 17
1.8 900 ppm 1152 ppm 1260 ppm 18
1.9 950 ppm 1216 ppm 1330 ppm 19
2.0 1000 ppm 1280 ppm 1400 ppm 20
2.1 1050 ppm 1334 ppm 1470 ppm 21
2.2 1100 ppm 1408 ppm 1540 ppm 22
2.3 1150 ppm 1472 ppm 1610 ppm 23
2.4 1200 ppm 1536 ppm 1680 ppm 24
2.5 1250 ppm 1600 ppm 1750 ppm 25
2.6 1300 ppm 1664 ppm 1820 ppm 26
2.7 1350 ppm 1728 ppm 1890 ppm 27
2.8 1400 ppm 1792 ppm 1960 ppm 28
2.9 1450 ppm 1856 ppm 2030 ppm 29
3.0 1500 ppm 1920 ppm 2100 ppm 30
3.1 1550 ppm 1984 ppm 2170 ppm 31
3.2 1600 ppm 2048 ppm 2240 ppm 32

There are three conversion factors which various manufacturers use for displaying ppm’s…

USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

For example,

Hanna, Milwaukee 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
Eutech 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Truncheon 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

Phase 2 in next reply




Fertilizers PPM

To discover the ppm of your fertilizer mix, you will require being able to gauge grams
and liters. Come across at the nutrient 3 numbers written on the side of a fertilizer
package, these are the percentage substances of the nutrients in the fertilizer. Each
one gram of that fertili
zer in to one liter of water, this will give 10 ppm per percentage point of the given

Example a 20-20-20 nutrient gives (10 ppm x 20) or 200 ppm of every nutrient for each
gram in a one liter of water.


Grams of fertilizer per liter = A/B
A = your desired ppm
B = 10 ppm x the % of nutrient in mix or your ppm = C x B
B = 10 ppm x the % of nutrient in mix
C = gram of fertilizer per litter.

So to make create a 200 ppm to 100 ppm to 200 ppm NPK mix utilizing a 13-0-44
ratio of potassium nitrate, a 12-62-0 ratio of monoamonium phosphate, and a
33-0-0 ratio of ammonium nitrate you would work in reverse from your single
P and K basis (it makes it the simplest in this case), and create up the N at
the finish. I have rounded values to the nearest 0.1 g for the following. You
would utilize 0.5 g of potassium nitrate about 200 ppm/910ppm x 44k and 0.2 g
of mono-ammonium phosphate at about 100ppm/(10ppm x 62P) in one liter.

Fertilizers PPM

This would provide you 89 ppm N (10ppm x 13N x 0.5g + 10 ppm x 12 N X0.3g),
124 ppm P (10ppm x 62 P x 0.2), and 220 ppm k (10ppm x 44k 0.5g). 111 ppm is
necessary to elevate the N to 200 ppm level, so we can utilize 0.3g of the
ammonium nitrate (111 ppm/ (10 ppm x33N) to take us up to complete. The
concrete mixture would give away a 188 ppm N, 124 ppm P, 220 ppm K mixture
in one liter of water.

To obtain more accuracy, you require combining big batch or getting an
improved range. You would require to make 10 liter set of the over with
a range that is only precise to the gram. If you blend your own fertilizer,
you can regulate your N basis to meet up your ph requirements, rather than
relying on adding acid or base, which is good. This works for formulating
hydro mixes, as well as for us soil farmers.




That is supposed to simplify things?!?! Lmao Im more confused than ever now! :grin: I plan on using the GH TRIO to simplify things, and maybe some additives if need be. Just thinking about running two plants in their own 5 gallon reservoirs, for my first time. Probably going to DIY the system.


Two questions.

  1. When calibrating the pH tester, do I need to use both 4.0 and 7.0 solution, or can I get away with one or the other?
  2. Do I need to get some kind of calibration solution for the ppm meter? I didn’t even know there was such a thing!


Research the device you have and see if it needs a calibration fluid or not and also try to calibrate your meter to 5.8 you’ll have to adjust to get it there but that’s quite simple so maybe a little of each wpuldnt be such a bad idea. I understand you need to save money however its better to avoid any crucial mistake right off the get go.

@xDeeTeRx I looked at your meters yes even your ppm meter will need a calibration solution



I know it. but how are you to learn it… if you don’t the info. go over it few times the better you’ll understand.
I gave it to you to copy and paste then read.
What i’ll do is i’ll simplify it for you.
Good thing i didn’t send you what i have on P H…lol




Thanks - I appreciate it - I’ll have to reread it a few times to really get an understanding.


These are the meters I purchased…


Yes I looked at them from the post above they will both need the calibrating solution…



Ok I simplified it for you …ok

Start with 600 PPm for week 1
900 PPm for week 2
1200 PPm for week 3
if you go over 3 weeks veg
1500 PPM week 4
1800 PPM week 5 and hold there
at bloom I flush and go to 1000 PPM week1
1300 ppm week 2
1600 PPM week 3
1900 PPM week 4
flush weekly…VERY IMPOTANT
and hold there until last 2 weeks and ad your bloom enhancers if your using them

this is double secret probation info…



@xDeeTeRx good for you bro
You got two of the best grow mentors here first post
I won’t add anything they got you cover
Except for this welcome to the best grow forum
Any Questions just tag me I’ll help when possible
Also pick up some calibration solution and check that cheap meter once a week they tend to drift a bit
Happy growing


You will also need pH up and Down, unless you are going to use something else?

the PPM meter is actually a TDS meter and the unit of measure is ppm. Learn something new, every post!

Welcome to ILGM @xDeeTeRx


Nice animal house reference.


Hi Guys. @garrigan65 . I’m well into my first grow, harvest soon. Admittedly I have not measured PPM thus far, 70% of my plants are monsters, the others are scarecrows. I didn’t pay any attention to ppm because I went really light on the nutrients and frankly there are so many things to learn that I needed to get solid with many other things first. Just got a meter and tested my runoff from a half dozen plants… have not calibrated the meter yet, and the run off reads about 200ppm. I’ll figure out how to calibrate it, and retest next watering.
With regards to your simplified chart @garrigan65. does it mean that in week 1 for example, you want your water going in to read 600ppm? Are you adjusting nutrients in the feed water to try to match those figures? Or, if the goal is to have your runoff at those numbers, what is it that changes the soil ppm? Adding nutrients? Thanks Oh, and also, the bloom enhancers, do you use them during Veg? or just Flowering? thanks


coming out, if not use more to get it to 600 ppm
and use bloom only during flower


Thank you.


Your very welcome, if you need some help with that a little on … just tag me and i’ll help you. Ok ?