pan, i am not adding any cal/mag.
last res change i ran out of Fox Farms, and i don't have much money.
so I used what i had. . . i picked up a gallon of CNS17 bllom and grow for $25 total.
anyways so i have CNS17 bloom in the res which has 2% calcium and 0.5% magnesium.
The rockwool looks like new on all sides but the top. . . on the top, there is a small amount of algea (less than one square inch) on the smal surface where the light gets to it, and this is only happening on maybe 30-40% of the cubes.
I just double checked my PH which is still at a steady 6.06. from what i can tell it isn't fluctuating much. . . however i just checked my ec, which is a whopping 2200 ppm. I am injecting co2, so that should help, but ill lower it to the 1600ppm suggested by my feeding schedule.
This yellowing has been going on for weeks though, and i am changing the res weekly. if it was deficient of something, it would make sense that it happens with every res change, but i don't think it would persist if it was just PH fluctuations or ppm.
it may also be useful to note, that there are some short plants in the wheel that didn't show signs of any yellowing until recently (this week).
It used to be only on the tops, so i thought it might be the heat wave we had 3 weeks ago when it got to be close to 100 degrees in the wheel, but it didn't go away and it has worked its way down to all of the fan leaves right to the base. And it is not all over, it clearly starts from the tip and works its way in on most leaves.
do you think i should try supplementing cal/mag?
Im not using RO btw. and my tap is about 150ppm.
thanks for your help.