200w aquarium heater
Why is my aquarium temperature jump?

I have a 200w heater aquarium HYDOR Theo tank.the temperature of 29 gal is jumping up and down like 13 degrees within 24 hours .. 77-90 anywhere in deg.the tank has been set for about 4 mths now.it has always had a + or – as I set it up 4th place and was never a concern. (All fish are still alive). But as the last 3 days her jumping like crazy. I have no head of power to overheat it.its not near a window, and fluorescent lighting is pretty cool .. house temperature is also a constant 70 degrees.

I lost $ 100 on disk to a bad heater, I personally would like get that thing in the tank right now and go buy another. It will be fine without a heater for the time it takes to go to the store and back. Follow the instructions on the heater to a T when you put in the tank. Do not connect everything at once, let it sit for a while so that the heater thermostat adjusts water temperature. A heater 200 watt is a bit large for a 29 also. You want to have 3.5 watts per gallon of water. In a small tank 3 WPG, in a larger tank, 5 WPG. BTW, the fluctuations in temperature cause untold stress to the fish. Stress is one of the major factors compromising the immune system of fish. Coat of stress-dose and get a new stove as soon as possible. Good luck.

24g Nano cube


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