heating big tanks

[mightieskeeper]

I got a 150 gallon aquarium for a great deal.  I have never had a tank this big.  My problem is I don't want to run a 500 watt heater because of monthly energy cost.  Im looking for better cheaper ideas to heat the tank.  Any suggestions? Ryan

[Luke]

Put it in your warmest room or wrap the tank with insulation.  But seriously the warm room thing would help.

[GrizzlysDad]

Bigger tank means bigger energy consumption, no getting around that unless you do an unheated tank with appropriate fish. Also means larger filtration which, you guessed it, larger energy consumption.
Having kept many large tanks I do recommend two smaller heaters in the 150g instead of one large one.
You can get better heat distribution by having a heater on each end of the tank. This also eliminates the "thermostat stuck and cooked my fish" syndrome because if one of the smaller wattage heater's stick on, it's not enough to kill your fish...and the other heater would not kick on if the bad one was always running.
You do have to fiddle with the heaters at the beginning to get them balanced but with all the preset heaters out there now it's pretty simple.

[Ron]

You don't necessarily need a 500W heater.

The size heater you need is proportional to the heat loss the tank may experience. If you keep the room at 78F, you wouldn't need any heater at all! 

I'm with Tony - 2 smaller heaters is safer than 1 huge one, but it's also a bit more expensive.

To help save on cost you can insulate with styrofoam to help reduce heat loss from the tank. I always have styro between my tanks and the stands to help alleviate any surface abnormalities to insure they're level, but it also insulates the bottom of the tank (more important if you have a stand that doesn't have a solid surface. Adding 1/4"-1/2" to the back usually isn't too hard either. Depending on how nice of a show tank or it's particular location, adding some to the sides may be alright or might look tacky.

Also make sure to keep a tight fitting lid! IMO evaporation is the greatest form of heat loss there is. Having a tight lid will not only mean your fish won't find the floor, but it'll keep the moisture (and heat!) enclosed.

[GrizzlysDad]

Yep, tight lids are a must for saving heat. I am usually obsessive about tight fitting glass tops. I absolutely hate the plastic hoods that are sold as an optional top.
Actually, the two heater method is only slightly more expensive in that you have to buy two heaters. Energy consumption for two 250w heaters are no more than one 500w heater.
In my fish room I don't even have heaters in the tanks...in the winter I heat the room instead.
In the summer I don't run any heat in there, but I do isolate the room from the central air.

[mightieskeeper]

This tank will be in a room that is 70 degrees all the time.  Is it possible to use 2 150 watt or 2 200 watt heaters to heat this big of a tank?

[GrizzlysDad]

This tank will be in a room that is 70 degrees all the time.  Is it possible to use 2 150 watt or 2 200 watt heaters to heat this big of a tank?

With the room being kept at 70 degrees you should have no problem with two 200w heaters. I usually run two 200w or 250w heaters in my 190g with no problems.