Please Help Determining Problem

Hi Everyone. First time grower; first time poster but I could really use some help determining the issues with my plants. My system is as following:

Hydroponics with Ebb and Flow
300 W LED
ph right around 6.1
ppm around 700
Room temp around 75 Degrees
Humidity 50%

The growth appears to have halted

I've tried flushing the system, cleaning the resevre, with new nuts starting off at low amounts of nuts thinking it was a nut burn, or some kind of deficiency. however did not resolve the problem.

I thought maybe light intensity is too high, so I just upped my light height from about 2ft to 3ft tonight. see if that resolves anything.

All of the discoloration appears on mid to newer growth.

Any help would be appreciated. Let me know if any other information is needed.

Do you have any pics with the lights off? Hard to tell what kind of discoloration is going on with your LEDs shining on them. Gives them a weird color.

Here are the requested pics with the light off.

Using RO?
Cal/Mag def!!!!!!!!!!!!

No RO, using reg tap water which is less than 100 ppm though.

Cal/Mag was my initial thought also, that's why I flushed the system and added new Nuts thinking that would solve the problem, however its been about 10 days since I have flushed it and I am still seeing this worsen.

Another thing to note is that the majority of the damage appears on the portion of the plant that is getting the most light ie directly below the light. the outer plants are not showing these issues yet.

Potassium is locked out due to pH being too high or potassium isn't present in adequate quantity.

Verify pH meter calibration.

Set pH at 5.8. Drift from 5.7-5.9 is ok.

I will calibrate the pH meter when I get home tonight. All my research says the pH acceptable range is from 5.5 to 6.5, that is why I have been setting it to 6.0 - 6.1 range. Is this not accurate?

If it is Potassium being locked out it should from the pH being to high and not inadequate quantity because of the flush. Right?

It has been a couple weeks since I have calibrated the pH meter. I will post results later this evening when I can calibrate the meter again.

2 snaps up!
Run the Cal/Mag too.

Hi,

So I calibrated the meter and it was pretty accurate. before calibration reading 5.9 after calibration, reading 5.8

I will add some cal-mag nuts and go from there. My thinking though is when I flushed the system and gave it new nuts that should have replenished the Cal/Mag and even potassium nuts in my reservoir. the pH is within the desired range. My PPM are not too high. Not sure where it went wrong. Maybe my nuts are bad? they are kind of old.

Be sure you add any nutes 1 at a time to your water, do not mix them and then add to water. You might give it a stir between adding to.

may have root slim...growing stops ph will keep going up
in my dwc my leaves looked like that at the end started like pic.

The roots appear to be fine, it was also one of the things I checked. besides the pH remains the same. It does not fluctuate much. I put some cal/mag nutes on it, hopefully the issue does not get any worse tomorrow.