Grow help requested! Dwc autos

Hey guys and gals…. Yet another issue, I’m sorry to keep bugging… Seems I can’t go a week without everything going to shit. So 10 days ago or so I did a full res change and it was a complete disaster. Long story short plants are alive but I feel like they are dying… basically I had them in fox farm trio with ppm @like 1700 for 3days before realizing, tried getting lower added water etc only got down to 1100 ish… so the upper leaves started to turn brown and rusty color again leaves dying etc. I did another full flush letting them sit in h20 no nutrients for 24 hours then added nutrients and ppm down to 500 for a few days and then 700 and now 800 or so… plants still look like death and I’m quite worried.

Also got a new hlg320xl 2 days ago it’s hanging 21 inches above the plants.

Tips now curling, browning, some crumbling to dust at touch… what do I do!. Is it light burn? Could it be nutrient burn again even a ppm of 700s? Is it too dry? Doesn’t feel hot at all at the leaves…

Thanks for any and all help everyone!

Auto flower Gorilla glue, critical purple, ak47
-Age of plant week 13 from sprout, 9 weeks of flower.
-Method: DWC with 4 air stones
-Vessels: Plastic tote
-PH 5.8
-PPM of nutrient solution 808
-Method used to measure PH and TDS - pH and ppm meters
-Indoor size of grow space 4 x 2
-Light system hlg320xl @ 21 inches above
-Current Light Schedule 18 on 6 off - veg+bloom
-Temps; 70-72
-Humidity; 45
-Ventilation system; Fansx3
-Co2; No
If growing Hydro some additional questions:
-Distance of liquid below just at net pot

  • white non slimy massive root balls in bath
    -Temperature of reservoir 68
    -TDS of nutrient solution 808
    -Amount of air to solution tons of air

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Not sure how to tag all the smart growers in here.

I will try to help you with tagging @oldmarine @MrPeat @kellydans can y’all give a hand here.

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@low @Hellraiser @Covertgrower


Looks like late stage calcium deficiency. Maybe phosphorous.
It looks like the effected area is mostly under the light?
Light stress possibly, was the new light a big jump over the other? You generally want a gradual transition to higher intensity.

I’m not really a dwc guy, see if others chime in.

Are your ppms on 500 or 700 scale?


Looks like you were burning your plants up with your old light because it was too close. Top portion of your plant looks burnt up.

How do you know this? They look way too young to be 9 weeks of flower.

Have you calibrated your ph meter lately?
Are you using calmag?
What order are you mixing and exactly what amounts are you feeding?
Good luck! :+1:t2::v::sunglasses:

I’m using fox farm trio for nutrients as per its schedule, adding 1tsp/gal calimagi. Think I should add more cal?

The light was a massive jump I think it was a blurple now hlg 320xl, think I should dim it down? Putting my hand above the highest cola feels just slightly warm.

Normally, 1/2 tsp/gal is plenty.

How high from the tallest cola is the light?
If your leaves are pointing up, your lights too close or too hot. Those leaves probably won’t get better but if you correct the issues at hand, you’ll salvage your grow.

9 weeks of flower.
How do you know this? They look way too young to be 9 weeks of flower. They are autos, they sprouted July 1st, they started flowering around first week of august and I totally agree they look way too young stunted etc… I dunno
Have you calibrated your ph meter lately? Calibrate it every few days, last was yesterday.
Are you using calmag?
What order are you mixing and exactly what amounts are you feeding?
I put 5 gallons of tap into large jug let it sit for 2 days, I add calimagi first 1tsp/gal then big bloom 4 tsp/gal, grow big 2tsp/gal, tigerbloom 1 tsp/gal, hydroguard 1 tsp/gal. Then I get it to ph 5.8 add it to tote and then ph the whole tote again to 5.8.

I just don’t understand what I’m doing wrong.

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Light is just under 21 inches above tallest cola.

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@Not2SureYet @Myfriendis410 is this a mixing order issue?

Don’t think that’s causing the issue.
I would definitely keep your light at least
18” -21”above the tallest cola at least till your leaves start calming down. Try not to change a bunch of things at once cause you’ll never know what corrected the problem. And you may end up with more problems and not know what caused it.

I think start with less light and less calmag. If you are 9 week in flower, it would be ok to cut calmag out all together. Good luck! :+1:t2::v::sunglasses:

One other thing, if you have a journal going, tag me in it.
if you’ll keep it all on that thread, it makes it easier to find and reflect on past problems.
You can always ask for help there. :v:

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Yeah I think with the nutrient burn fiasco and then the new light etc I introduced too many changes at once and now have no idea what the problem is.

I dimmed the light to 50%, will see.

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Thanks for the help everyone!

Still worried because I still don’t really know what’s going on. Besides dimming the light to 50% should I be doing anything else?

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9 weeks into flower, you would be ok to trim a 3rd of the growth underneath the canopy. Trimming the big old fan leaves will help with air flow and allow more light into the lower buds.

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Thank you so very much, next grow I will try the grow journal and will def tag you in it. I wasn’t sure if I was allowed to because my seeds didn’t come from ilgm :face_with_monocle:


Looks like nute burn to me: I also see some minor clawing which indicates N excess. Also remember that an excess, especially in hydro, can look look like a deficiency.

Remember that all damaged plant material will not recover: look to any new growth for improvement. The problem with it being in flower is the plant won’t show big improvements as it’s concentrating on flower production. I agree with @spyonyou that a defoliation is probably a good idea. I’d run my numbers down around 600 ppm or so until things perk up. FF nutes frankly would not be my first choice in hydro.

Also as pointed out: silica first, cal mag then everything else. If not running silica you probably should.

I know you’re on 18/6 but running autos. That said, you will hit your DLI with that light in 12 so you’re just wasting $$ FYI and could contribute to the plant metabolizing the higher salt level which don’t help.


Thanks so much for the reply, you all are amazing.

I’ve never added silica to my system, any recommendations? Brand dose etc? (Tyvm)
And I’ll def switch my light to 12/12 if you think it will help!

I’ll water it down a bit and try to keep the ppm around 600? How long would ya say to keep it a little low for? A week? Few days? And slowly try to go back up?

And I’m completely done with FF nutrients once this is grow is over, gonna try jack321 or mantis.