TDS meters, which of these 4 is a good purchase?

[good drown]

i'm not sure how much i really need one, i grow in soil, but i figure it cant hurt right?
so i have a few choices. which if these is the best purchase? i would love to get the cheapest one, but i have concerns it may not be that accurate. i dont think i need it to be super accurate, more consistent. here are my options...
$40
The Sunleaves TDS Essential Digital Pen measures total dissolved solids from 0 to 9,999 parts per million with a resolution of one part per million and includes a data hold feature for temporary TDS reading storage


$80
Oakton’s Waterproof EcoTestr TDS Low is a convenient TDS meter that doesn’t let dirt or moisture keep it from delivering accurate readings. It features a clear LCD display, a waterproof, dustproof housing, and automatic shutoff! It also has a self-adjusting TDS factor, allowing TDS measurement in an array of applications. Measures TDS from 0 to 1990 ppm with a resolution of 10 ppm. Unit measures 6 1/4" x 1 5/8" x 1 1/8" and includes four 1.5 V batteries that provide over 200 hours of use.


$105
The GroCheck TDS Meter provides easy-to-read TDS measurements quickly and accurately The GroCheck TDS Meter provides easy-to-read TDS measurements quickly and accurately. The meter is simple to set up, hangs on the wall and comes with a TDS probe, 6' cable, 12V DC adapter (no batteries needed), 1500 ppm calibration solution, calibration key and instructions. The GroCheck TDS Meter measures TDS with a range of 0-1990 ppm, a resolution of 10 ppm, and an accuracy of ±2% full scale. This meter also features an adjustable set point of 500 to 1600 ppm, and an LED alarm that flashes when the measurement varies from the set point ±100 ppm. The GroCheck TDS Meter is dependable, featuring a water-resistant, tough outer casing that protects the meter from water, dust and vapor. The meter carries a 2-year warranty, with a 1-year warranty for the probe.

$135
Gardeners can easily measure and maintain nutrient strength levels with the waterproof Truncheon from Bluelab. Truncheon reads in EC (0.2-3.6), CF (2-36), and TDS in both 500 and 700 ppm scales (100-2520). Accurate within ± 4% of reading with a resolution of .1 EC, the Truncheon runs on three AA alkaline batteries and comes with a five-year manufacturer's guarantee.

much obliged for your time

 

[shaunmulok]

Get the Truncheon it reads in EC
PPM's are a crock of shit and vary pen to pen
PPM is just a conversion of EC so better of just reading EC's

 

[kp^]

Truncheon +1

Shop around tho.. I got mine for $110 with s/h.

 

[good drown]

damn thats what i was afraid of, the most expensive was the best
on the upside, it has a 5 year warranty. if i get it from my local hydro store, i can just return it there, instead of having to send it in to the manufacturer
so how important is it for me to be checking my EC?
what should i notice/change once i get it? what is the acceptable EC range for soil?
thanks shaun and kp

 

[Greyskull]

i think ph is of much stronger importance than ec, but it is valuable to know exactly what your plants can take and what they cannot.
using an ec guage is a lot like a tachometer while driving a stick shift imo... you can watch the tach and shift accordingly or use the sound of the engine to tell you when its time
with plants you can watch the ec or watch the leaves... personally i do both (i check & watch)

good luck
stay safe

 

[good drown]

thanks greyskull, thats a great way to put it, the tachometer. thats basically how i felt.
so what EC is too high? the main point of it is to not go over a certain level, right? is there more to it?

 

[Greyskull]

what ec is too high?
in my uneducated opinion the ec is too high when the tips of leaves turn yellow (aka burnt tips). some plants can take more than others... some do better with more some do better with less. there is really no exact "thats too high' becasue if the plant is 'taking it' the plant is 'taking it'....

glad you like/understand the tach analogy... some people have never driven a stick shift and they dont know hahaha

 

[good drown]

is there a range that people try and aim for? if 2 of my 7 are light feeders(yellow tips), what EC should i try and not go above just to start using the meter? i am just looking for a rough ec for light feeders, and one for medium. then from trial and error i think i should be good to go.
thanks again!

 

[Greyskull]

thats where the trial part comes in man sorry hehe
you gotta find where they burn at

but for fun, and just my opinion,
light feeders = ec 1.0-1.3
med feeders = ec 1.5-1.8
heavy feeders = ec 2.0 & up

 

[good drown]

PERFECT!!!
thank you very much greyskull!!!
now i just have to buy the ................




......................bluelab truncheon. i love the fact its batting 1000 (5/5)

 

[FreezerBoy]

I'm DWC which feeds more efficiently so, take this with a grain of salt. I start at 1/2 the recommended dosage, take that measurement or future use, and wait to see if the plant want's more or less.

Mfg nute formulas are not based on plant health but, on how much they can cram down your plants throat without killing it. Chances are you can grow great weed using a leaner formula then that on the bottle.

i think ph is of much stronger importance than ec,

I have to agree. pH controls what does and does not get eaten by the plant. I've done grows using pH alone. BUT, I don't know I could have without the lessons my Truncheon taught me and truthfully, grows using both EC and pH control were better.

$40 is easier on the wallet than $130 but, take comfort in this, if you go Truncheon, you've got the gold standard.

 

[DiscoBiscuit]

IMO, you don't need an expensive TDS meter, they're not as temperamental as pH meters. I agree that EC is best but they're typically more expensive.

It's easy to estimate EC if you know your ppm conversion factor.

If calibration solution is 1382.... the conversion is .5 (1EC = 500ppm)

If 1500, conversion factor is .7 (1EC = 700ppm)

My meter is .5. A 900ppm reading is ~1.8EC.

 

[FreezerBoy]

You forgot at least 7 other conversions. "TDS" and "PPM" leave you with an 89% chance of being misunderstood. Hanna alone uses 4 different scales so Hanna users have a 75% chance of being misunderstood just among themselves. EC is universally understood.

If all one has is $20, there are EC pens for that price. If one's already made a purchase "TDS" and "PPM" will do. If the purchase is in the future, do yourself and the hobby a favor and stick with EC.

 

[mule420]

I started with the sunleaves one it was a piece of junk... I have the oakton one now and it works great! However I need to step up to reading EC so I will be getting the one from blue lab...

 

[DiscoBiscuit]

Mine is a Milwaukee and the pdf seemed pretty straight forward. Wasn't aware of the hanna variations, sounds like different types of readings instead of 4 standards though. Thanks for the info.

 

[FreezerBoy]

Hanna uses four different conversion scales: 500, 640, 650 and 700.

 

[DiscoBiscuit]

I think 640 is aussi and 650 is UK.

 

[shaunmulok]

i found this a while ago after i purchased a new meter for a friend and was getting 2 different readings from 2 different pens i was getting worried until i read this chart and noticed his new pen was a different conversion rate

The conversion from EC (electrical conductivity), typically measured as ms/cm (milliseimens per centimeter),to TDS (total dissolved solids) displayed in PPM (parts per million), can be both technical and quite confusing. EC is THE standard and should be used whenever possible by all to avoid confusion, however, nutrient meter manufacturers around the world insist on confusing the situation with the use of varying conversion factors. All TDS electronic meters that give PPM readings measure nutrient strength in EC and then convert the EC using a tiny micro-processor inside the meter to PPM. The problem here is that different meter manufacturers use different conversion factors. For example, Hanna uses a conversion factor of 0.5, Eutech uses 0.64 and the Truncheon uses 0.7. If you are about to buy a meter for the first time or need to replace your old one, BUY A METER THAT DIPLAYS EC.

 

[good drown]

ok guys and gals, i got the bluelab truncheon!!!!!!!!!!
thanks for the help, i am so glad i asked.
what kind of solution do i use. is there a storing solution, or calibrating solution?

one again, thank you very very much!!!!!!!!!!!!!

 

[shaunmulok]

hannah make a solution for storing probes, they also have a test solution
The truncheons are factory calibrated