Jalapeno yellowing

I got a plant from my wife for my b-day, a jalapeno plant, and it turns out it had aphids, in another thread someone told me that if I spray it with a diluted soap solution that it would kill them, well it got rid of some of them but I have another problem that is now occurring. I don't know if it's a nute issue or a combination of a aphid and nute issues:
I got a liter bottle of KoolBloom and mixed a weak strength mixture (about 400ppm's) and started watering it with this just after it started producing flowers, after I started doing this the plants lower leaves started yellowing and some have even fallen off.
On top of that I can't seem to get any of the flowers to pollinate and grow a dang pepper. This has been a total nightmare of a grow and i feel aweful because this plant was a b-day present. What could I be doing wrong with this plant? I transplanted it into a Scotts garden soil mixture with a very low P-K-M it was something like .8-.1-.5 ( I don't remember to be exact but it was weak) I am growing this guy inside under a 400 watt MH with temps in the low 60's at night and low 80's during the day. Any idea's if this is aphids, my nutes, or anything else? I have stoped giving it anything but water until I get some info on what's going on with it.

Scotts growing soil is the main problem. Check out the Library -Peppers, on the Dirt Doctor.com site. Hope this helps.

This is what dirtdoctor.com says in the library under peppers:

Topic

Peppers Some of Howard’s favorite peppers are:

MILD:
Pimento – red
Big Bertha
Jupiter
Golden Bell – yellow
Top Banana – yellow
Lilac – purple
Jingle Bells – red, heavy producer, good for beginners
California Wonder – popular but has diseases, poor choice

HOT:
Cayenne - red
Chili Piquing - red
Jalapeño
Serrano
Habanero – orange & red
Spanish Spice – yellow
Squash – yellow
Purple Peruvian - purple

I'm obviously missing something man, what does this have to do with the dirt? I'm going to go poke around the site for a min now...