new leaves turning yellow

[mojo21]

i have an indoor setup running 6 600w lights, run to waste sytem. i have an exhaust fan and pedestal fan running temp is around 28degrees. im using the correct nutrients and and a teaspoon of ph down into the barrel. after 1-2 weeks of growing the new leaves are turning pale and yellow then dying. while the older ones stay green. it has happened twice so far. i have used this sytem before and it worked perfect. please help

 

[maineharvest]

Gotta see some pics. Yellow usually means nitrogen shortage but not really sure about pale. Are you sure its not nute burn?

 

[Cali*Style]

Sounds like to much nutes to me...?? Pics would help.

 

[lyfr]

dont think its nitro def. new growth will rob old growth for nitro yellowing old growth first. N is a mobile nute meaning it can move around plant to where its needed most...sort of. i saw this before but cant remember what it was. i would guess ph...wait, maybe it was sulfer? let me look around,err, or uh...you could. do you have a ph tester or are you just guesstimating? is the yellow starting at tip of leaf...need pics

 

[lyfr]

http://www.mjp.com/ic/showthread.php?t=11688 check this link i found...i remembered right(amazing!) sulfer def/lockout= pale young leaves. sounds like iron or zinc may cuase similar symptoms. ok, im done try to figure this out...without pics thats the best i can do fotr ya! BTW, ph issues will cuase lockout

 

[mojo21]

thanks for the reply lyfr. i read the links you attached and it looks like my ph levels were too high around 7, maybe this is causing some sort of nutrient lockout. ill monitor it from now on and see if it gets better. cheers