Problems!

Got 5 bubblelicious and one unknow strain. Started off good until now. they've been groing since 19 aug and i'm pretty sure there supposed to be taller than this, also all the leaves are light green and not growing out ass much, some of the plants leaves have been turning yellow at the bottom and been getting brown spots on the leaves as you can see in pic number 5. There been white blotches here and there on the leaves also. I need much help in figuring out this problem. 400 metal halide/hps been using superthrive (not too much) and molasses but I have grow big, tarantula, and more superthrive on the way. Ph has been around a 6.8 to 6.5. Any help is appreciated

IMO its a little early for molassas and I'm not a fan of it anyway ( yukky smell in the jars later on) but I had the bright green problem once too and my expert at HTG told me it was lacking Nitrogen so I slowly upped the N and sure enough they turned to a darker more natural shade of green. Now yellowing at the bottom could be something different. Losing some of the lower leaves will happen later but shouldnt happen yet only a month into the grow.
Good luck with it, I think they look pretty good all in all. If they stay shorter and bushier thats a good thing.When you flip them over to flowering soon, they'll more than likely stretch upward almost like its overnight.