tank temp with out a heater

[sphelps]

Originally Posted by globaldesigns

I don't run heaters or chillers. My display is 180G with 100G sump. Also running MH for 9 hours a day, with actinics for 13 hours.

My temp is usually around 77, now saying this my house is also climate controlled with HRV, so summer to winter, my house doesn't really change.

Seems like an odd thing to do, how do you prevent a temp drop over night?