Heating...or Rather Cooling Problem

[Jinkz]

Looking for a bit of help from some of the more knowledgeable or technical amongst you. On my 300ltr Tangs tank I have my heater currently set at 24*c but the water temp is still hovering around the 27/28*c temp. The heater was originally set at 26*c and was at a 45* angle in the middle of the tank along the back wall, but I've noticed over the past week that the temp seems to stay high despite me turning it down a little almost every day. I live in Israel and although it's warm outside at the moment the house is nice and pleasant and around 22/23*c during the day I'd say. The tank isn't sitting in any direct sunlight and I'm now getting a bit concerned about the temp. The heater is coming on when the temp reads 27*c and stays on till the water hits 28*c and then goes off.

Anyone with any idea what I should do?

 

[fluttermoth]

Have you checked with another thermometer? What kind of fish are in there?

 

[KittyKat]

Try turning the heater well down, it could be mis-aligned. What wattage is it? The other common cause for high temperature is that it may be broken.

What lights do you use? How far above the water are they? How long are they on for? Is the temperature the same before they come on and right before they go off?

Are you measuring it in an area with good circulation? Are there any differences in temperature between top and bottom of tank?

Is there good circulation around the heater?

 

[Jinkz]

Have you checked with another thermometer? What kind of fish are in there?

I have a glass thermometer on the opposite side of the tank, reading the same temp....water also feels warm to the touch.

Try turning the heater well down, it could be mis-aligned. What wattage is it? The other common cause for high temperature is that it may be broken.

Tried turning it down to 23*c...no joy. It's sat at 45* angle. back right of tank...never had issues with that positioning before on this or any other tank. Starting to think the thermostat is duff.

What lights do you use? How far above the water are they? How long are they on for? Is the temperature the same before they come on and right before they go off?.

Two of T8 lights approx 15cm above water surface. One Daylight 60w, the other 15w Purple. Daylight is on for 10hrs, 15w Purple is on for approx 2hrs in the evening. Temp doesn't change whether they are on or off.

Are you measuring it in an area with good circulation? Are there any differences in temperature between top and bottom of tank?

Is there good circulation around the heater?

Very good circulation actually. The heater was sitting right under my spraybar and half of that was pointed down to help internal water flow. Both sides of the tank, top and bottom reading same temp. Circulation around heater also very good as I have an bubble line under it so there is always circulation around the heater.

 

[StandbySetting]

If it were me I'd buy a new heater, if it's unresponsive to any changes of setting you're making that would definitely be ringing alarm bells for me, I like to replace heaters every 2 years, I've had so many that have malfunctioned, if it's still under warranty see if you can get a replacement, if not buy another one.

 

[Rogue4Fish]

I'd try turning the heater OFF for a couple of hours and see if the water temp drops. If it does, the heater is at fault.

 

[KittyKat]

I would also just buy a new heater. If the heater is not at fault, then it is still good to have a spare one.

 

[Jinkz]

Going down to get another heater tomorrow but meantime done a 30% water change which brought the temp down to 26*c. Heater is unplugged for the moment, will see how things pan out leter this evening. Don't really want to leave it off all night