Tds replacement help

Any suggestion on a tds that doesn’t cost a lot or is there any way to really test ppm to know which one is working correctly…my current one is reading way higher then the free meter i just received

I went thru many of these pens for the same reason, before finding the VIVOSUN TDS/EC/ph/TEMP all in one …have had it over a year now and rarely needs calibration…there are PPM solutions you can buy if you are concerned but I don’t believe any of the PPM/EC pens allow user calibration of PPM only the PH can be user calibrated if I remember right…

Currently using a apera ph pen and might just get the tds meter also

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I had that one too and mine was never stable/repeatable

Which one are you using now

Are they using the same scale? I notice on in in Celsius and one in in Fahrenheit, is there a way to change settings?

BTW - I use the Apera PC-60 all in one. It’s a professional level meter and had replaceable probe head and maybe a soil probe head available too. Great pen. I check it once a month and calibrate maybe twice a year but mine is never off more than a few hundredths of a point


got if off Amazon

I thought that too at first since the reading is 2 times the other and typically PPM to EC is that ratio…the temp function should not affect the PPM readout


Do the temps jive? I’m literally about to walk out the door!
Good Luck!!

With both in ppm and Fahrenheit its still a big difference

temps are off if my math is right 24 C is 75 F but I don’t think temp figures in to the PPM measurement but I do smoke

This one

that is the 3 in 1 model…I have the 4 in 1 model…not sure if there would be any quality difference between the 2…


Which apera pen? There are several. My ph60 has been a valuble durable and acurate tool for over a year now.

You will get what you pay for.

Went with the apera pc60


I forget which one, was about $50 it was my first multifunction when I stepped away from the single mode pens…It came in a very nice case with 2 calibration solutions for PH in little bottles…and you are right I may have just got a bad one but it never held the ph calibration very long and then it just stopped working after about 4 months…it was recommended by several growers on another forum site

For some reason when testing jack 321 ppm it reads for 2 seconds then shows tds ppt under the battery icon but as soon as i take it out the mix it instantly switches back to ppm… have you seen that?

Never mind reading the manual now

On TDS mode it switches to PPT from PPM because of the limited display space. PPT is parts per thousand so 2.20 PPT is 2200 PPM…did I say that right? LOL!
It switches back to PPM because out of the solution the EC/PPM drops dramatically.

It’s the same number you just have to move the decimal with your mind…

BTW - I’m 99.9% sure Apera uses the 700 scale as opposed to the 500 scale. Hopefully someone will confirm.
So on feed charts you should be looking at the 700 scale as your guide to EC/PPM.

Yea…i had to read manual but thanks for the help