First time grower new member help

hellow i love this site long time reader first time member and grower thanks already for all the help everyone.but now i need more help planted clones on the first shocked for 5 days left on vacation oct 11 just got back i have 3 strains (part of my problem ?) grand daddy purps black domina and sun kiss the gdp and bd look the same groth wise the sunkiss is tall the leaves on the bottom half of most of them are yellowing, gray and brown spotting and some are dying. the spotts almost look like spray paint the others are fine im using house of gardens full scheme on oct9 ec was at .75 ph5.7when i got home it was .97 (normal?) and ph of6.5. is this a nut problem or disease none of these signs are appearing to spread to the other strains. i bought what i thought was good stuff to minimize any problems but i know they are like kids.