What is wrong with my seedling

[solocup]

I started 2 seeds of chem91 x deathstar . Both have a ph of six and a ppm of between 2 and 3 hundred.

One is doing great with no problems and the other one started with small brown spots on the first true set of leaves.
It soon followed by complete death of the leaves and now it has moved up to the second and third sets.
The roots are nice and white and the Rez temps are 66 and steady. System I am running is dwc single buckets. I am using a phone and that is the reason for the clustered sentences..

here is the pic and I hope I can fix this before it is too late.

 

[zub0]

u sedling is vegging and u have a Phosphorus deficency

 

[solocup]

u sedling is vegging and u have a Phosphorus deficency

I changed the rez last week and it has continued.

It has the same level of nutrients that the other one has and its doing good.

I will change it again and up the ec and see if it stops...Thanks for the input

 

[trichomes]

I agree with zub0, What nutrients are you feeding it? here is a related picture for you.

 

[Mono]

It has the same level of nutrients that the other one has and its doing good.

Not all plants need the same nutrient requirements, even plants of the same strain and seed bank can have totally different phenos.

 

[solocup]

I changed and uped the nute strength twice and it is getting worse.

I even changed the nutrient brand from GH to bontanicare.

I don't know if it makes a difference but I did.I have also added magical each time as I am using RO water.

I also noticed that the roots are starting to turn brown above the water line on both.Temps are 65 to 68?

Didn't think I could get root rot at those temps.

One other thing , I also noticed the one with the problems has less air bubbles going into its reservoir.It seemed to slow down anyway after I changed to Botanicare and I am going to go buy a new air pump to marrow.Thanks for the help

 

[Mono]

I would recommend using only plain water if the problem is getting worse...

 

[Cultivator]

If using R/o water its likely cal/mag thats the problem.

Exactly what are u putting in there in what doses?

For advice on anything DWC related check out my journals, i will try answer all questions.