Best thermometer
 

Man, it's hard for me to be current here for some reason. Anyway, I need a heater for my 90 gallon tank. I know I need a 200 and 250 watt or two 200 watt heaters, but I've heard good and bad about almost every kind. What're your opinions?

I use one HYDOR THEO heater at 400 watts for an 80 gallon tank and same for 75 gallon tank. Have used them for the last five or six years and no complaints.
Also like the VISI - THERM heater as well and have a couple of them as well.

I recommend two heaters in a 4-foot tank, one at either end next to the filter outflow and intake (if you have a canister with these at opposite ends which is good). This way the water entering and leaving the tank is heated for an even temp as the water is not getting too far away from the heater. And 200w minimum for each. Higher wattage heaters work less hard and thus last longer. Another advantage of two is if one should fail, you still have the other which overnight in the winter can be the difference between live or dead fish. Heaters are the one thing in the aquarium that you should never go cheap on.

My 150w and 200w heaters have been going for 15 years; I can't even remember their brand. But most recently I bought a Fluval, the one with the coloured digital temperature screen. While I have never had a failure (yet) with the 100+ heaters, 3 50w heaters have failed. I now have a 150w in my 10g, and a 200w in my 20g and 33g, and they work fine.

Another option is a canister filter with a heating unit. I have an Eheim on my 90g with this, and that tank never varies more than .2 or .3 of a degree. Of course, I don't know if this is the same in the tanks with two heaters as I have no digital thermomenter probe in those.

Ok. Thanks for the suggestions!