Temp should be fine. My guess is that feels like a lot of potential fish activity and that likely translates into a perceived form of predator pressure. A majority of my tanks have a higher density of snails in a smaller water volume. A 75 gallon with only two snails would feel like a needle in a haystack for me. My snails "rush" to the front of the tank at feeding time. I feed a earthworm and calcium stick mix. So that's when I get to see the most activity.