Heaters..how large?

I am going to place an order for sand..Caribsea dry special grade, and figure I better get my heaters at the same time.

The DT is 65gal and the sump will be in the basement. The sump will be probably as large as the DT. I'm thinking I will do 2 heaters and we keep our house very cool. 60 at night, 68 daytime. How does one figure out what size of heaters to buy? I am thinking the Eheim Jager brand and get two.

Going through Fosters & Smith since they were one of the sponsors of our swap.

Thanks-
Susan

I use a 200 watt on my 65 and it seems fine. You could go bigger but that's more expense.

Get two for redundancy. Set one at a slightly cooler temp so you only use both if needed. Is say 2 150w would be fine. That's what I had in my 75.

Two smaller ones, I don't like having one big enough to overheat the tank, been there, done that. And a third for a backup.

A general rule of thumb when I was down in Chicago was 5 watts per gallon. Here in Duluth, in my basement when it gets down to 60F, I start having heaters fail (burn out). Indeed, I think splitting the load between mutliple heaters is a good failsafe, as is having a heater on hand ready to go in the event that one fails. It seems that heaters and pumps are the two most failure-prone items in any tank, so backups for both are ideal.

DFS had Ehiem heaters on sale last time I checked.

I have 2 heaters too, ran off of my reef keeper. So the heaters are set at 82, but the reef keeper keeps them at 80. If something ever fails, they won't cook the tank.