Phosporous Deficiency?

[Boradan]

I went away for about 24/36 hours and came back to this...

Ladies are 77 days old - Both Fruit Punch Auto (Heavyweight Seeds)
RDWC system.
Using the full line of Remo Nutes along with Great White

I removed the ladies, washed off their roots in the shower and placed into pH'ed water (19C ) temporarily.
Roots were fine. They were stained brown from the Velokelp, but no slime or rot in them.
Drained the system and ran through about 40l of plain water to get rid of most of the gunk.
I then filled the rez with Water and Nutes to the following:

*Water is ppm 100-150 tap water. Dechlorinated for 24 hours - luckily I had some prepped and ready to go before I left.

pH: 6.2
ppm: 755
Water Temp: 18.5C
Air Temp: 25C
RH: 45%

Light: 2 x Viparspectra 600W reflectors (one on each plant @ 18")

The issue is mainly on top growth, with a few lower leaves showing a few spots forming.
I raised the light a few inches in case it was stressing them, but no Light burn at the minute)

I am leaning towards Phosphorous being the culprit here due to the slightly reddish stem that can (barely) be seen in the pic, although this plant has ALWAYS had reddish stems from the start.

Note that the pic was taken under a Blurple as the markings are more noticable.
I can get a photo with just the flash if necessary (no natural light in the room).

The grow has been running at pH of 6.0-6.2 since Day 1.

The second plant in the system is showing a few minor spots, but nothing like this one (both the same strain).
I am thinking I should maybe drop the pH slightly to 5.8/5.9

The grow is in my sig.

 

[Boradan]

Some more pics of both plants with just the flash:

 

[Rev. Green Genes]

It does not look like deficiency to me, I think you are right, get the pH to 5.8, they look very well fed to me. Calcium has better uptake at 6+ but the fraction of P foes down over 5.5 till it's no longer available at all at 6.4 or so.

 

[Autobeast]

could be boron deficiency.how much calmag u been feeding? as that could be a reason. sorry to see ur troubles. happy growing

 

[Boradan]

could be boron deficiency.how much calmag u been feeding? as that could be a reason. sorry to see ur troubles. happy growing

Magnifical at 1.5ml per litre

 

[Boradan]

It does not look like deficiency to me, I think you are right, get the pH to 5.8, they look very well fed to me. Calcium has better uptake at 6+ but the fraction of P foes down over 5.5 till it's no longer available at all at 6.4 or so.

What would all the brown marking on the leaves be then?

 

[Rev. Green Genes]

What would all the brown marking on the leaves be then?

a pH lockout of Phosphorous. It looks like a deficiency, but the P is just in the wrong form for the plant to take it at that high a pH.

 

[Autobeast]

Magnifical at 1.5ml per litre

ur good then bro thats spot on. they look very healthy top work. hope u get it sorted. happy growing

 

[Boradan]

a pH lockout of Phosphorous. It looks like a deficiency, but the P is just in the wrong form for the plant to take it at that high a pH.

Ah. Gotcha now.
Had me confused there.
Hopefully the flush will have helped with the lockout.

ur good then bro thats spot on. they look very healthy top work. hope u get it sorted. happy growing

Am dropping the pH now. Will try to get it to 5.8.
Takes a while as I add about 1-2ml of ph Down, then give it an hour to circulate 6 times so it gets well mixed.
Don't want to overshoot.

 

[Rev. Green Genes]

Ah. Gotcha now.
Had me confused there.
Hopefully the flush will have helped with the lockout.


Am dropping the pH now. Will try to get it to 5.8.
Takes a while as I add about 1-2ml of ph Down, then give it an hour to circulate 6 times so it gets well mixed.
Don't want to overshoot.

It's not you, I'm a confusing bastard. I try to say things normal, but the science data just finds it way in there.