I started tomatoes indoors under CFLs like I have for years, but this year every one of my tomatoes have yellow sickly-looking cotyledon/first leaves and are taking forever to develop their first true leaves. I don't remember ever seeing this color predominate the way it is this year.
I have them in Burpee Seed Starting mix in paper carton cell trays sitting on a wicking mat stretched over a board and draped down the sides, pulling moisture up from a reservoir below. This keeps the mix consistently moist by wicking action.
I germinated them at 85 degrees soil temp and then once they were all up let them drop to 65 degrees (ambient temperature in that part of the house). Could that be too much of a drop for seedlings?
My well water here might be a bit on the high pH side, possibly as high as 7.0. It has no chemicals and has not been softened. Well, I guess I do sometimes mix a bit of warm water with the cold in the reservoirs, and that is softened, so maybe there's a residual salt in there? Any chance that's the culprit? And the Burpee starting mix does say it has some food in it, so it could be an excess of fertilizer salts too soon for such tiny seedlings?
My lighting is a shop tray with four 48" 32W T8 flourescents @ 6000-7000K, hung a few inches above the plants. These have worked fine in the past. They always end up a bit spindly at planting time but the plants have always stayed green.