Answer: The warmth probably didn't hurt the seeds unless it got too warm 90oF, then that may have killed the emerging seedlings. The extra heat may have dried out the seeds and again that would kill them quickly. A dark room is fine as long as you put theseedlings under lights as soon as they start germinating. I'd try again by not putting the seeds directly on top of the water heater, but maybe near it to get some warmth, but not overheat. Keep them well watered and of course use fresh seeds. They should sprout in 7-10 days.
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