It sounds like they may be leggy. This can be caused by low light and/or high temperatures.
What kind of lights are you using? Fluorescent tubes should be 1-2" above the plant tops and on for 16 hours per day, so you may not be giving them enough light.
A soil temperature of 82-84 is pretty hot for tomato seedlings. Try adding a fan to your light timer to keep them cooler. This will also help make the stems stronger.
TomNJ
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