leaves yellowing and brown edges

[JohnEmad]

hey gang,
Hope you can shed some light on this for me.
Using remo nutrients in coco/perlite, in Autopots. Over the last week readings are ph 5.7 to 6.3, ppm - 775 to 950
lowered the lights 3 days ago to 14" and then saw this and raised them back up to 18-20 inches.
1st sign of anything other then a slight burn from nutes on some leaf tips throughout the grow.
Day 50.
I am thinking potassium deficiency now.
thanks for your comments.

[JohnEmad]

Just a quick update. Some of the new growth is also coming up almost yellow.
After reading a ton of articles and a chat with my local grow shop experts it was basically concluded it is most likely a deficiency of potassium due to the plants being hogs during the stretch. I decided to add a double helping of Remo astro flower that has 1 - 6 - 11 so lots of potassium. If there is no marked improvement overnight or things worsen I will remove the plant from the system and flush thoroughly with ph'd h2o. and then top water with a weak nutrient solution. Have to check the roots for rot first as another check.
Will post the results.

[SoOrbudgal]

Good catch JohnEmad I hope it's no rot.

[JohnEmad]

me too SoOrbudgal,
I am prepared to treat the roots if needed. Things went very nicely for most of the grow and then Bam! they hit puberty and things go sideways...

[JohnEmad]

The plant was continuing to show signs of stress and the tops were sagging over so I flushed as per GWE instructions with 3 times the pot volume of ph'd water.
First I removed the plant from the autopot system. I set it over a tub on top of another container to keep it out of the old solution and flushed 3 times with h2o @6.35 ph. After each flush I decided to record the ph and ppm.
Flush #1 - ph-6.85, ppm-1172
Flush #2 - ph-7.18, ppm- 641
Flush #3 - ph 7.44, ppm- 227
I then top watered with a very weak nutrient solution. 1/4 strength.
Seeing I was mixing my res at 5..5 to 6.3 and ppm between 700 and 1100 over the course of the grow I most likely had a ph imbalance and too high a nutrient level in the roots.
There is no rotten smell from the roots so it appears I messed up with too much. Hmmm what is the #1 piece of advice for autos and nutrients. Less is Better. and every strain can be different.
My Cream Caramel hasn't missed a beat and the other NLx shows only minor signs of leaf stress.
Will update in a couple days.

[JohnEmad]

good news for the stressed girl. Things are stable after 36 hrs so back into the autopot system and lets relax and let them do their thing.
Seems running different strains in 1 reservoir can lead to trouble sometimes. good to learn.