Month old seedlings in dwc yellow color and brown/copper spots- nutrient deficiency?

Hey guys i have five seedlings that are about 4 weeks old in dwc. i gave them straight RO water for about 3 weeks. they began to get these brown spots and were very yellow. i added 40 ppm of fox farms grow big hydro formula and the next day the difference was noticable. they were greener and definitely grew a little. however, after that the spots worsened and they went back to yellowish gradually. so i decided to add nutes gradually about every 24 hours. i went from 40 to 60 to 100 to 150, 200, 250, 350, 400, 450, 600 and now i just bumped it up to 700. these spots seem to be a deficiency because the growth is painfully slow also and they recieved no feeding until week 3. i have been adding nutes to try to find that perfect level and i have been looking for a response from the plants that never seems to come. i just made the increase from 600 to 700 minutes before writing this but i do not want to add any more until i figure out what the deal is. the pH wants to rise in the rez so i adjust it to 5.7 and let it run to about 6.2. the only other thing i have been adding to the rez is few drops of superthrive when i make a water change (about weekly). there are 4 long airstones attached to 2 airpumps in the bottom of the rez. the brownish color on some of the root mass is dust from the hydroton pellets i guess i didnt wash them off well enough. but yeah take a look at these pics and give me your opinions please. i could really use the advice i dont know what to try next.

P.S. they are under a 2 foot, 6 lamp T5 fixture, and temperatures stay between 74 and 78, not sure about humidity
View attachment 1278986

i could use some input on this also...ive got almost the same setup as you...but i use a single dual pump with the same 2 airstones.brown spots...yellowing of the leaves...roots about the same size.but im not using a ppm meter and feeding it jacks classic and epsom salt...other then that started them the same as you...didnt feed till i had roots out the net pots.


but +rep to you for starting a thread i was too lazy to start....hahahaha
and +rep to anyone that can help us out.....
and best of luck bro...first time with dwc..so im sure im fucking a few things up

im with you man this is my first dwc too we gotta be forgetting something. hopefully someone jumps on this soon. whats that epsom salt for again? Mg?

twokhps said:

im with you man this is my first dwc too we gotta be forgetting something. hopefully someone jumps on this soon. whats that epsom salt for again? Mg?

Click to expand...

yep..and i also use powdered eggshells in my water for calcium..forgot that before

true ive never heard of that. where the hell do you get powdered eggshells? lol

twokhps said:

true ive never heard of that. where the hell do you get powdered eggshells? lol

Click to expand...

i make it..boil some eggs and remove the shell...or use leftover shells...boil them in water for about 20-30 minutes...then i crush them into a fine powder and mix it into my water when i add my nutes. use about 4-5 eggshells per gallon

Both of you guys have no cover over your rockwool...

I use 1" rockwool layer my 3" net cup with 1-2" of hydrotron rocks then fill it around the rockwool to keep it in the middle, then more on top as the plant grows.

You may have nutrient lockout... I would flush for a few hours and then put them in a solution around 400 PPM and leave them there for a week. What is your PH?

djruiner said:

i could use some input on this also...ive got almost the same setup as you...but i use a single dual pump with the same 2 airstones.brown spots...yellowing of the leaves...roots about the same size.but im not using a ppm meter and feeding it jacks classic and epsom salt...other then that started them the same as you...didnt feed till i had roots out the net pots.
View attachment 1279016View attachment 1279017

but +rep to you for starting a thread i was too lazy to start....hahahaha
and +rep to anyone that can help us out.....
and best of luck bro...first time with dwc..so im sure im fucking a few things up

Click to expand...

Get a PPM meter your frying those...

Weedler said:

Both of you guys have no cover over your rockwool...

I use 1" rockwool layer my 3" net cup with 1-2" of hydrotron rocks then fill it around the rockwool to keep it in the middle, then more on top as the plant grows.

You may have nutrient lockout... I would flush for a few hours and then put them in a solution around 400 PPM and leave them there for a week. What is your PH?

Click to expand...

ive got covers over the rockwool..just take them off before i take it out the box....the fans blow them around if i dont.and it starting doing it before i added nutes..while it was in r/o water...ph around 5.7

djruiner said:

ive got covers over the rockwool..just take them off before i take it out the box....the fans blow them around if i dont.and it starting doing it before i added nutes..while it was in r/o water...ph around 5.7
View attachment 1279088

Click to expand...

How old? 2 weeks?

Weedler said:

How old? 2 weeks?

Click to expand...

right now its a little over 3 weeks...that pic was about a week old..just dont take many pics while its inside my box that was all i had showing it with its cover on it...the first pic is how it looks now at 3 weeks

OP:i think ur problem lies with ur nute mix is too strong and ur riding the ph rollercoaster....not rinsing the rocks well will result in ur ph rising
the best thing to do when a problem like this rises is to change the rez
DJ:same for u,change the rez but lower ur feed
i also would drop anything organic that goes in the rez

moash said:

OP:i think ur problem lies with ur nute mix is too strong and ur riding the ph rollercoaster....not rinsing the rocks well will result in ur ph rising
the best thing to do when a problem like this rises is to change the rez
DJ:same for u,change the rez but lower ur feed
i also would drop anything organic that goes in the rez

Click to expand...

thanks man...ill give it a shot...cant find any info on how much to feed since im using jacks classic...plan on using the fox farms line after this grow..but i wanted to get a final answer on jacks classic in dwc...since i could not find an answer...im all about learning new shit...growing all the easy ways got old...not the end of the world if a toast a few plants in the process

djruiner said:

thanks man...ill give it a shot...cant find any info on how much to feed since im using jacks classic...plan on using the fox farms line after this grow..but i wanted to get a final answer on jacks classic in dwc...since i could not find an answer...im all about learning new shit...growing all the easy ways got old...not the end of the world if a toast a few plants in the process

Click to expand...

no prob
how is it so far,besides the overfeeding?does it keep a stable ph?

moash said:

no prob
how is it so far,besides the overfeeding?does it keep a stable ph?

Click to expand...

doing good..nice strong white roots...got the ph in my big dwc and my mini dwc leveling out pretty good...i drop it to 5.2-.5.3 with my res changes and its up to about 5.5-5.8 the next day and stays there.ive been feeding them about an 1/8 tsp pre gallon right now.....guess its 1/16 time...just dont see how thats enough to make a difference

One problem you guys have is that you are not monitoring how much your plants are eating. If you get a PPM meter and record the data over a few days, you will get an idea. Ideally in a 24hr period you want the water to drop a bit, the PH to rise a bit, and the PPM to stay the same. The changes are more subtle on young plants, very obvious on older plants.

If your water has dropped and your PPM has risen, your nutes are too concentrated.

If your water has dropped and the PPM have fallen, your nutes are not strong enough.

If your water has dropped and your PPM stays the same, plants are drinking and eating at the same rate.

Ensure this is happening before you start looking of specific deficiencies. In the mean time you can try to correct some of the problem by foliar feeding. Also, bad spots or damage on leaves does not heal...look to the new growth the tell you how things are going.

djruiner said:

doing good..nice strong white roots...got the ph in my big dwc and my mini dwc leveling out pretty good...i drop it to 5.2-.5.3 with my res changes and its up to about 5.5-5.8 the next day and stays there.ive been feeding them about an 1/8 tsp pre gallon right now.....guess its 1/16 time...just dont see how thats enough to make a difference

Click to expand...

try raising ur ph from 5.8-6.3,i thought u kept it at 5.7
ur a lil on the low side
that could very well be the problem,i was thinking u fried them to lockout cuz u had no meter
1/8 dont sound like too much but ive never used it,so thats ur call...what is the recommended dosage?
but since the ph is so low to begin with......change the rez and raise the ph
that should get u started to recovery

Heisenberg said:

One problem you guys have is that you are not monitoring how much your plants are eating. If you get a PPM meter and record the data over a few days, you will get an idea. Ideally in a 24hr period you want the water to drop a bit, the PH to rise a bit, and the PPM to stay the same. The changes are more subtle on young plants, very obvious on older plants.

If your water has dropped and your PPM has risen, your nutes are too concentrated.

If your water has dropped and the PPM have fallen, your nutes are not strong enough.

If your water has dropped and your PPM stays the same, plants are drinking and eating at the same rate.

Ensure this is happening before you start looking of specific deficiencies. In the mean time you can try to correct some of the problem by foliar feeding. Also, bad spots or damage on leaves does not heal...look to the new growth the tell you how things are going.

Click to expand...

i would to say that u should top off ur rez every day and measure after the top-off

Weedler said:

Both of you guys have no cover over your rockwool...

I use 1" rockwool layer my 3" net cup with 1-2" of hydrotron rocks then fill it around the rockwool to keep it in the middle, then more on top as the plant grows.

You may have nutrient lockout... I would flush for a few hours and then put them in a solution around 400 PPM and leave them there for a week. What is your PH?

Click to expand...

how could nutrient lockout occur other than pH troubles? i set the pH to 5.7 or 5.8 and let it rise to about 6.2. i had considered pouring a bunch of pure water over the pellets to rinse them further but i dont want to soak the cubes and cause problems with that. ill make some covers for the nets. is that just to help with mold, and other things associated with light?

moash said:

OP:i think ur problem lies with ur nute mix is too strong and ur riding the ph rollercoaster....not rinsing the rocks well will result in ur ph rising
the best thing to do when a problem like this rises is to change the rez
DJ:same for u,change the rez but lower ur feed
i also would drop anything organic that goes in the rez

Click to expand...

anything i can do about the rocks now?