Betta heater

[Teo04]

HI,

I have a 10l tank, and I am trying to stabilise it at 25.5 to 26.5 degrees celsius. I have a 25 watt heater, but the temperature, which is set on 23 degrees has gone up to 28 degrees, but when I set it to 25 degrees, it went from 28 in the day, to 25 in the night then back to 28 in the morning.

Does anyone know how to stabilise it properly???

 

[Essjay]

Do you mean a 10 litre tank, or a 10 gallon long tank?

Most heaters are badly calibrated; they don't heat the water to the temperature on the setting. The way to set a heater is to get the water to the temperature you want using a thermometer that sits inside the tank. Then turn the heater till the light clicks on, and slowly turn it back down till the light clicks off.
Thermometers that attach to the outside of the tank are not accurate as they are affected by air temperature.

Is there a light on the tank, and if so, what kind? Some lights get hot enough to raise the temperature of the water when switched on, and the water temp drops back down when the lights are turned off.

How warm is the room during the night? If it gets cold, it could keep the water cooler than during the day.

 

[Teo04]

Do you mean a 10 litre tank, or a 10 gallon long tank?

Most heaters are badly calibrated; they don't heat the water to the temperature on the setting. The way to set a heater is to get the water to the temperature you want using a thermometer that sits inside the tank. Then turn the heater till the light clicks on, and slowly turn it back down till the light clicks off.
Thermometers that attach to the outside of the tank are not accurate as they are affected by air temperature.

Is there a light on the tank, and if so, what kind? Some lights get hot enough to raise the temperature of the water when switched on, and the water temp drops back down when the lights are turned off.

How warm is the room during the night? If it gets cold, it could keep the water cooler than during the day.

AT the moment, it doesnt get too cold at night... I have LED lights

 

[Essjay]

LED lights don't get very hot so they shouldn't be affecting the temperature.

It could be a badly calibrated heater. Provided the thermometer is one that sits in the water, try adjusting the setting as I suggested. Ignore what the setting actually says.

 

[Back in the fold]

Do you mean a 10 litre tank, or a 10 gallon long tank?

Most heaters are badly calibrated; they don't heat the water to the temperature on the setting. The way to set a heater is to get the water to the temperature you want using a thermometer that sits inside the tank. Then turn the heater till the light clicks on, and slowly turn it back down till the light clicks off.
Thermometers that attach to the outside of the tank are not accurate as they are affected by air temperature.

Is there a light on the tank, and if so, what kind? Some lights get hot enough to raise the temperature of the water when switched on, and the water temp drops back down when the lights are turned off.

How warm is the room during the night? If it gets cold, it could keep the water cooler than during the day.

All of that is true. Heaters are very poorly calibrated. You will have to tinker with it until it gets where you want it to be. Might take a couple days of monkeying around.