Planning to switch to an LED from an HID because of heat issues is a bandaid fix, you need to correct your environment. Not to be rude or presumptuous but judging by this thread you need to spend a lot of time reading the basics of indoor growing in stickied threads on this forum and others, the GrowFAQ from Overgrow (search Google), etc. You don't have the base of knowledge you need, so get working on that.
In the mean time, here are some issues I can point out based on what you have posted so far:
-Way too much light and way too close. You need very little light to grow healthy seedlings. You could take away the 400w HID and CFLs and just use the T5 for at least a week or two until these are back on track.
-Over-watered and under-aerated medium. Your soil is compacted and not allowing enough oxygen to the roots, and you are likely not allowing enough time to dry out between watering. Take a pot, fill it with your soil, let it sit in the environment for a few hours to a day or so until very dry. Lift the pot, note the weight, and then use that knowledge to only water the other pots when they have reached that level of dryness. It may seem counter-intuitive, but it is much easier to kill a plant by overwatering than it is by underwatering, particularly in a soil application.
-You're feeding way too early. Seedlings don't need anything for the first week or two of their life cycle in a soil application like this. Stick with plain water until you have these things healthy.