Tank heater won't drop below 28C

So I have 2 aquariums.One right next to the other.The first one is year and a half old,but the new one is over a month.Now in both of them I have heater and both heaters are set to 24°C.In my older tank everyting is fine,the temperature is as it is supposed to be,but in the new one the temp won't drop below 28°C and I do not know why.They are literally next to each other and there is no difference in lighting or natural sunlight.The only difference is that the older one has a thicker glass,and that's it.Could that really be that important?I don't know what to do and I would really like to cool it down somehow,so I would be grateful if someone had any kind of solution.Thanks

 

Do they have different types of heaters? To me it sounds like one heater may have busted and is now keeping the temp way to high(had this happen prior).

 

Yes they do,how do I know if it is busted?is there any visible signs?

 

There can be some signs like cracks or starting to fog up, but it can also just be something internal that doesn’t appear. I’d just try and get a new heater if you can, preferably not the same brand.

 

If the thermostat goes bad there usually aren’t any outward signs other than loss of temperature control

 

The heater is probably broken and won't shut off once the desired temp is reached.

I would just get a new heater.

 

Then I will buy new one as soon as I can.

 

I think glass thickness makes a difference with ambient air temp. I had one of those minI heaters I was using in 3 gallon acrylic plastic or whatever and it would overheat but I tried it in a smaller back up hospital tank under two gallons but with very thick glass and it never went as high in temperature.

 

Yep,definately heater mulfunction,now it is at 32°C
I turned it off and hoped for the best until this afternoon when I can get a new one

 

Yep,definately heater mulfunction,now it is at 32°C
I turned it off and hoped for the best until this afternoon when I can get a new one

Yikes, I’m glad you were keeping an eye on it. Your fish should be ok until the evening, just raise the temp back up slowly(1-2 degree every hour). If you can I’d also increase oxygen in the tank since it’ll take a bit for it’ll cool down.

 

I just bought an airstone and thought the same thing.Now the temp is at 26°C and the fish are swimming so much better.Just hope it will stay that way,thanks everyone!