Yellowing in 10 day old seedlings.

My friend has three young seedlings. All three have a lighter than normal green color, and the lower leafs are turning yellow. The newest growth is nice and green, but will soon turn light green and then yellow like the rest. The main stem is also purple up until the seed leafs, then it turns green.

They are in MG Organic soil, with no nutes added. Watered with 7.0 a few times. Grown with CFLs.

From what I have read, it seems like a N deficiency, but this should not be happening so soon. Could it be a PH problem? I can't test the soil, only the water. I assumed the soil had a low PH so I am using 7.0. Could the soil already be high PH and I am just making it higher?

I have exactly the same problem so I hope somebody will suggest something.

I ruined 20 seeds until now. Every time I, I grow them they start green then turn slowly into yellow then die. I tried hard to figure out the cause.
Now I'm more sure that it is a Ph thing. or water type issue.

I only have a soil ph meter and I'm not sure if it's accurate. It reads 7 ph.
I have no water ph meter.
I'm use bottled drinking water from supermarket.

Now is this water ok? Is distitled water better?
How can I reduce ph in soil?

Soil acts as a natural buffing agent and you don't need to worry about PH 99.9% of the time.

Both of you will need to add a lot more information to receive any sort of accurate help. ie. Lights(type/size/total), containers(size/medium type), what nutes are you planning on using? How often do you water/feed? The more the information about your setup the better the advice you will receive.