Some yellowing

[Triniminicano]

Wussup guys, newbie doing a DWC grow you guys were great with an earlier question back with another.

Everything was going great, entering 9th week getting ready to change over to 12-12 in 1 more week. I've noticed for this last previous week, 2 of my 3 plants started showing some yellowing around the tops. Not significant yellowing but its noticeable. And its only in the tops. Thought it might've been nutrient lockout, PPM was a little high so I adjusted it to 700. Ph was at 6.2 dropped it to 5.7. Started to see positive response that very same day, the lush green was coming back. Now a day later the slight yellowing is returning.
As a newbie I'm not sure if it's normal in this stage of veg for this slight yellowing or its really issues.

I need y'all to do what y'all do best and drop some knowledge here!

This morning
Res temp 75°
Tent 77°
PH 5.7
PPM 700

 

[Old Salt]

It could be a zinc or iron deficiency; or possibly your plant is too close to the light.

Why not start a grow journal under Grow/Grow Journals on the menu above. It helps to see what you have been doing getting to this point when diagnosing problems.

 

[Triniminicano]

After a couple days monitoring it, I came to the conclusion it was nutrient lockout. The ph climbed up to low to mid 6's every 4-6 hours. Ordered some ph down, been using vinegar and some ice packs to ph down and keep the res water cooler. Saw positive results almost immediately, lush green came back and started rapid growth again.

Glad I went through this! PH and PPM, SUPER IMPORTANT!

✌