How long does it take to heat a 125g?

[Matman1110]

I recently bought a used 125 gallon tank with some used heaters (theo hydor 200w & 400w). I have filled the tank about 3/4 full and wanted to test the heaters. I put them in on opposite ends of the tank and plugged them in about 45 minutes ago. The temp of the tank was 72 degrees and it has not budged. Do these heaters take a long time to warm up and heat the water? I want my tank at about 79.

Thanks in advance

 

[D-Smeezy7]

I put one heater in a 150 gallon and it took overnight for me so I'm guessing yours will also take a few hours

 

[ezy33]

It will take longer if you don't have something to move the water, air stone or a powered filter will work. Most heaters have a light that lites when the heater is on. IMO you should be up to temp in 4 to 6 hours with 600 watts.

 

[meBNme]

I have a 300watt in my 150, it raised the temp from70 to 78 in about 4 to 5 hrs. If you look closely, you should be able to see a mirage like water movement, swirling, within an inch or two of the elements. As the water heats it stirs up and displaces. This of course only when its raising temp, not merely on again off again maintaining temp.