Confusion about ppm reading

[Newbgrower78]

Hi growers community,

My plant has been looking a bit "sick" lately. I made a mistake and fed it twice in a row (2 feedings with nutes 7 days apart), after that it looked like it was being fed too much so i've only given it water when it was dry.
As you'll see in the pics (i hope) the tip of the leaves are showing slight signs of nute burn.so I bought a TDS meter and measured the runoff and it was at 224ppm. (no x10 on the display)
I'm going to keep it on a schedule of 3x water/1x feed from now on.

If it was fed too much shouldn't the reading be much higher?
And what is a good ppm for a small plant?

thank you very much for the advice!

[gbauto]

Can you provide some info on the media you're growing in as well as lighting/environmental conditions?
I use Jacks 3-2-1 dry nutes in all of my grows(RDWC, coco, and soil) at the same amount.
The solution will end up at about 750ppm(500 scale) and they thrive.
I also feed every time they are watered.

[Newbgrower78]

Hi gbauto,
Thanks for you r reply...

I'm growing in Plagron Batmix, Light is viparspectra 300W, humidity is about 47%, temp at 25°C, tent is 1,7mH, 60cmW.
I used 3ml/L plaron bloom and 1ml bio bizz calmag/L (Last feeding)

Also, the stem is starting to turn red-ish, puprple...should i be worried about that?

Much appreciated!