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200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 10:52 am
by larkea
My 200W heater is set to 26°C but the thermometer reads 24.8°C. It's a brand new heater, and the tank is 120 liters. Anyone else had this issue?
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 11:18 am
by angler_lee
Yep, that's a common problem with some heaters. What brand is it? Cheap ones tend to be off by a degree or two. Also, where's the thermometer placed? If it's near the filter outflow, it might read lower.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 11:38 am
by elenalife
I had the same thing happen with my old heater. It was sketchy as heck. Ended up replacing it with a more reliable one. You might wanna check if the heater's thermostat is calibrated right.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 12:17 pm
by Sailor
Is the heater fully submerged? Sometimes if it's not, it can give weird readings. Also, how long has it been running? It might take a while to stabilize.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 12:42 pm
by larkea
angler_lee wrote: ↑Sun Jun 22, 2025 11:18 am
Yep, that's a common problem with some heaters. What brand is it? Cheap ones tend to be off by a degree or two. Also, where's the thermometer placed? If it's near the filter outflow, it might read lower.
It's a Fluval heater, and the thermometer is on the opposite side of the tank from the filter. I'll check the calibration.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 1:21 pm
by angler_lee
Fluval's usually pretty reliable, so that's odd. Maybe give it a day or two to see if it settles. If not, you might need to adjust the thermostat manually. Some models have a tiny screw for that.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 1:36 pm
by elenalife
Yeah, I'd give it some time. My new heater took like 48 hours to get stable. Also, make sure there's no draft near the tank. That can mess with the temp too.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 2:04 pm
by Sailor
If it's still off after a couple days, you might wanna contact Fluval. Their customer service is usually pretty good about replacements if it's defective.
Re: 200W heater set to 26°C but reads 24.8°C
Posted: Sun Jun 22, 2025 2:43 pm
by angler_lee
elenalife wrote: ↑Sun Jun 22, 2025 1:36 pm
Yeah, I'd give it some time. My new heater took like 48 hours to get stable. Also, make sure there's no draft near the tank. That can mess with the temp too.
True, drafts are sneaky like that. I've seen tanks near windows or AC vents have temp swings.