I have a issue with my Guppy tank i have the temp set to 26c but it spikes and drops from 24.7 to 27.3 is this ok or is the heater dieing? Its a 150W in a 60L tank. Also temp probe is on other side of tank from heater

Your problem might be not enough circulation? Maybe most of the hot water is staying down one end it could also be the room temperature, making it fluctuate. Is it insulated?

What brand is the heater?

A big heater on a small tank will be more prone to temp fluctuations depending on the quality of the thermostat in the heater..

I wouldn't worry about a range like that as it will be happening reasonably slowly.

I agree with Alan. You are only talking about a difference of 2 and a half degrees.

As said, room temperature can make a difference.

That would be a pretty normal hysteresis for most heater thermostats

Its not insulated

I have moved the temp probe around so the temps changing all over the tank

Its in the lounge so it gos from 10c over night to 20ish when the heaters on

Ill pull the heater out when i do tank clean today I think its a juwel but ill check (i do know its old so that could be the issue)

finally the temp changes throughout all the day so if thats to to much of a problem i wont worry about it as much

Oh I do however have a heater grad on it could this affect it?

Like alan says, sounds like normal hysteresis. May help to increase circulation a bit, but I wouldn't worry about it. it's not a big change and it likely is over a few hours anyway.

Oh I do however have a heater grad on it could this affect it?

A what?

Like a heater protector? I have one on my turtle tank, and it doesn't affect the temperature.

yeah protector (fail speller here lol) I didn't think it was a issue the red spot loves sitting on it

Shouldn't make any diference. Stop worrying you don't have a problem.

sweet thanks for the advice guys