Heater

[AnthonyB]

Best heating option for 180 gallon aquarium? 

[Fish Folk]

I'd by two of these

200 watts might seem shy for a 180, but I think it could work fine if you aren't constantly trying to lift temperatures up 20+ degrees above room temperature. 

[Kristinn]

I would first consider if you need to heat your aquarium at all. Most of the fish we keep in the hobby do fine at room temp.

[nabokovfan87]

you're looking at 2x of the fluval e300's.

If the tank is longer, over 4 feet long, I highly recommend dual heaters. If you're doing 10 degrees above ambient, I highly recommend the fluval e series.

Edited May 4, 2022 by nabokovfan87

[Brian]

I know there is so much information and controversy on this.  
Why not three 100 watt heaters?  One at each end and one in the middle.  If this isn’t enough add a fourth and divide the tank into quarters?  If one of the heaters fails either stuck on or off  it won’t be catastrophic.  
just a thought- good luck