Were I you, I'd check the Fox Farms feeding schedule. (the link is in my signature) It's a weekly schedule you can download and print. Follow it closely. Big Bloom isn't a stand-alone nutrient, it's a catalyst tea formulated to compliment the other two in the three-pack. Micro's and other goodness are in the Grow Big for growth stage, and Tiger Bloom for flowering stage.

Way past time to transplant.

If you are getting good soil, why screw around with it? Mixing different soils isn't a good idea in the first place. Why did you add your own mix...are you re-using the soils? (very bad idea till you know what you are doing)

What's the ph of your melted snow?

Remove dead leaves...? Yes
Remove dying leaves...? No

Would lower your 400w HPS to within 18 inches, and check the increase in heat with the back of your hand. Right now yuo are way too far from the plants. During the winter I was getting the lamps within 12 to 14 inches.