Help my babies are yellowing

Hannigan Drake said:

I have a Rainforrest66 with Vortex sprayer for my mothers (well still seedlings atm) with a 400W MH.
I also have a Reverse Osmosis filter, so my PPM starts at 001.
This morning when I checked on my little babies, they looked perfect, but when I looked in on them later, they started yellowing on the lower leaves.
Does anyone know what the problem could be, I think it might be Calcium deficiency but am not 100% sure.
The seedlings are both Nirvana Femanized seeds, the bigger one is Chrystal and the smaller one is Snow White. Root growth is strong.
Much Thanks in advance for and info/help.

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Easy one mate... when you see the yellow spots on nice green foliage it is almost a sure sign of overwatering. now I know that sounds hard to believe(everybody hates that answer) but answer me this... how often do you water, how large are your pots, and how much water do you use when you water? watering should be done once every few days and can easily be checked by lifting potted plant and telling by weight. when they get good and light, use enough water so that it starts to come out of bottom drain holes just a little. then let it sit till it gets light again. just my opinion but it is a mistake I have made before and looks just like it

bubblegumwidow said:

oh you are hydro huh? just cut yor flood time down by a few mins and that will clear it up mate!

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