DWC grow - leaf yellowing, necrosis, please help

[cbrdread]

Hi all, grow newbie here. been googling and searching through forums and the web for a fix since last night but no luck on finding the exact thing; problem is so many other yellowing issues can have more than one cause.
This is a trial grow before putting in quality, paid for seeds, so im trying to familiarize myself and work out my kinks.

Plants are at 23 days from seed, im yet to use a full dose of nutes for fear of nute burn. Notice the top right corner of photo. Any and all comments are welcome and greatly appreciated.

HYDRO GROW

Strain - Not sure, got them from a friend
# of Plants - 3
Grow Type - Hydro
Grow Stage - Veg
Setup - DWC 5 Gal bucket
Light - CFL
Nutrients - Botanicare Pro blend grow, liquid karma, voodoo juice
Medium - Rockwool/hydroton
PH - varies between 5.6 and 6.0
RH - 55% to 70%
Room Temperature -77 to 86
Solution Temperature -not sure on the exact temp but been using ice water bottles to keep res cool

 

[PhishyPhil]

it looks like a nute Deficiency, but i cant say for sure because im a soil guy.


wheres the bubble heads when u need em?

 

[cbrdread]

it looks like a nute Deficiency, but i cant say for sure because im a soil guy.


wheres the bubble heads when u need em?

at first i thought it was foilar burn from the spray but after research magnesium deficiency best described what i see on the leaves, added 1 tsp per gal of epsom salt, which is less than what the MJ bible suggested, when i did my res change on 06/26/10. should show improvement within a few days, other than that they're coming along quite swell..pics on progress soon

 

[BloodShotEyes]

Cbrdread , Go to the Deep Water Culture forum and check out Roseman's sticky thread about Tips and Tricks and do the 8 step recovery remedy, The man knows what he's talking about and the 8 steps usually fixes problems in DWC.

 

[cbrdread]

i narrowed it down to 2 culprits..Mg deficiency and substandard tap water. after applying epsom salt there was a drastic reduction in the leaf browning. still got one or 2 random leaves with it, thus the shitty water assumption. everything else is good so far.

 

[420Chic]

figure out if your water is hard or soft. If you have hard water then you need to add a product to help out. I use Bob's Brew Watermax along with SM-90 and I don't have nearly as many problems. My first grow was so bad, but from trial and error I figured alot out. I too thought that it was a mg deficiency then I added calmag to my res and fried the shit out my strawberry diesel. Talk about pissed off, but try your water before adding the nutes. I don't have the buckets I have the small 6 pot tank. do the 8 steps and then start with your water. I know it sounds stupid but it's not. I really hope it helps.

 

[420Chic]

did you soak your rockwool before using it, I know it starts out with a high ph. Just a thought. you said your ph was between 5.6 and 6. you can make your ph to pick up certain nutes if you have the guideline. between 6. and 6.5 is where you will have a good uptake of the mag if that is truly a problem. I keep my res at about 6.2 i have slight yellowing of my Grape Ape but not the Grand Daddyu purple. Crazy! So take a look at your water quality and then your ph and I think this may get you on track, after the 8 step remedy. which does work.