Calcium (Ca) help with deff

[Smallzz420]

This is my first post and i need some help.
I think that this is a Calcium deff.

I have 2 mothers (danky doodle x ak-47) got the seed from a friend
(The problem is only on 1 of my plants)
They are under 10-26 watt cfls 5-26k and 5-60k
Veg for 9 weeks on 18/6
My room is 3.5' by 4' they are in soil
Ph of soil is 6.3
R/H is 40-50%
Temp is 73 lights on and 68 lights off
Grow big from ff
water with R/O water with a ph of 7
wet/dry water cycle

I think i have a Ph problem and it's lock out my (Ca) from what i have read on the net so far. im new to this and would love some advice. I started flushing, with r/o water i cant find any lime around here. I just want to know if there is any thing else i can do to help my baby.
This is my first grow and i'm scared.

 

[flyfishinrock]

Try some "liquid calcium" kill two birds with one stone as it will also raise your ph, most hydro stores should have it. I am assuming its low, anyways. Whats the ph? do you ph adjust the water?

 

[Smallzz420]

I have been reading on R/O water, people say that you really need to add Cal/Mag to it because it lacks calcium and other minerals, could this be my problem using R/O water?
The ph of my run off is 6.4, my water is 6.5 with nuts is this to low for soil? i didnt check my Ph at first, this is my fisrt grow and i over looked the most critical part. I have a good Ph tester now
well one thing is nice i have learned from this, i just hope its not to late to fix my mistake
i'll be reading all night trying to learn as much as i can.

 

[flyfishinrock]

your ph sounds perfect to me, but some plants like it a lil higher or a lil lower; for now though I wouldn't mess with it. RO is a blank slate as far as nutes go, there's nothing. Most ferts are lacking in trace minerals to begin with as the makers expect variations in the minerals within different municipal water supplies, and its real hard to make them stable when mixed as a concentrate so they short change us. Try the cal-mag, the directions are accurate so for once you can follow the bottle.