1.5 weeks and PH issues. Need some help.

I was hoping it would not come to this but my girls are looking like they have a Ph problem. So here is my first post; I used a good organic soil in one huge pot and mixed in some cheaper soil and some perlite that had nutes in it(dammit I know I didn't notice till it was too late). I haven't grown in 4 years and I guess I am a little rusty. I have two really happy girls that are growing great, I mean right on schedule. Both are 1.5 weeks and are very happy and working on their 3rd or 4th node and already have seven leaves on the new nodes...anyways one of them, the best looking one has always had wierd marbling colors in the leaves which concerned me from day one, I might try to get pics. Also I have plants about a week old doing well in that soil also. I was thinking maybe the perlite casued a hot spot becasue of the nutes that caused the marbling on the nicest plant. These are bagseed so the genetics are unknown. Then what leads me to believe there is a real problem with the cheaper soil that I mixed in because the plants in it are doing trerribly next to the 90% organic ones. I am going to replant in organic with my smaller pots but in my large one I want to know how to fix the Ph becasue all the plants are doing great and some are ready for their own pot which takes care of them but the two established large plants are staying. Also one a foot away is growing without the smae marbling. I hope this made sense, I am stoned. Thanks in advance.