Tank overheating and I dont know why

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

Sparrow0v0

Aquarium Advice Newbie
Joined
Sep 9, 2022
Messages
2
Hi! Please help.

My tank is 190 liter / 40 gallon.

Inside I have a heater(unknown make), a eheim 200 pick up filter, a small bubbler.

I bought the filter a couple days ago.
I havent actively used my tank for a while, only recently getting some new inhabitants.
Inhabitants include a couple amano shrimp, giant African shrimp, 2 blue rams, 3 mollies, 1 red tailed shark, 1 bristled nosed catfish, 1 yoyo loach, 1 devil's horn snail.

My tank keeps over heating massively, my floating thermometer saying it's over 100°f!
I hadnt realised just how hot it had got until I brushed past the tank and felt it. I turned the light on to find fatalities. I've lost two additional yoyo loaches, 6 neons and an additional bristled nosed catfish.

I've attempted partial water changes to bring the temp down over the last few days but I can't pinpoint what is causing this extreme heat.

I've currently taken the heater out, which when I touched it was cold. I also took the small bubbler out which was giving off a little heat but it's tiny, surely it can't be that?

The tank used to have a built in filter system but I've turned it off and got the new one because the old one just wasn't doing its job anymore.

The eheim doesn't feel hot but it's the newest thing in the tank.

I've turned everything off right now, removed the heater and bubbler and I'm going to slowly return the electronics and see what happens. Will be getting a new heater later today.


There are lights, but the lights had been off over night so I'm certain it's not them.

Despite the hot temperatures, and the shrimp looking quite uncomfortable, everything else seems to be somewhat enjoying the heat being more active (but not too active, they dont look restless).

I'm looking for any other ideas I might not have thought of. I hate losing fish because they are so sensitive. Worst thing is I was convinced to get more fish recently when I had wanted to really sell on the tank but here we are. I do have a soft spot for fish.

Ambient room temperatures are around 18-20°c.
 
100f/ 37.5c seems too high for anything to still be alive, so i would try a different thermometer. A quick google search has indentified gas bubbles can get into the thermometer and cause liquid thermometers to read higher than the true temperature.

If its not thermometer error then do what you are doing. Trial and error.

I cant really see why a filter would cause excessive heat, but thats the new factor in the equation. Maybe an electrical fault? Same with the airstone. The obvious cause would be a faulty or misadjusted heater. How long have you had the heater? I tend to find they only last a couple of years before they need replacing. Lights, even LEDs will raise the tank temperature by 2 or 3c if you don't have a lid to prevent the heat escaping so that wouldnt explain a 17c temperature rise.
 
100f/ 37.5c seems too high for anything to still be alive, so i would try a different thermometer. A quick google search has indentified gas bubbles can get into the thermometer and cause liquid thermometers to read higher than the true temperature.

If its not thermometer error then do what you are doing. Trial and error.

I cant really see why a filter would cause excessive heat, but thats the new factor in the equation. Maybe an electrical fault? Same with the airstone. The obvious cause would be a faulty or misadjusted heater. How long have you had the heater? I tend to find they only last a couple of years before they need replacing. Lights, even LEDs will raise the tank temperature by 2 or 3c if you don't have a lid to prevent the heat escaping so that wouldnt explain a 17c temperature rise.

Hi, thank you tor replying to me and offering your advice.

I bought a new heater today along with another thermometer however even that is saying the temp is 90°f, same with the floating thermometer. I've attached photos.
It was insanely hot earlier and now it's much cooler to touch.
I'm so confused.
Still no new fatalities at least.

I had left the filter on whilst I was out and it's definitely not that at least.

Currently the new heater is in but switched off for now.
 

Attachments

  • 20220909_162636.jpg
    20220909_162636.jpg
    154.5 KB · Views: 19
  • 20220909_162710.jpg
    20220909_162710.jpg
    122.9 KB · Views: 15
90f is better than 100f.

With the heater off it could still take a day or 2 for the temperature to drop, especially with the light on. Its better to let it drop naturally than force it down with cold water changes. Just keep an eye on it to make sure it doesn't drop too much before you turn your new heater on.
 
Just to be sure, what kind of lights are you using? Also, what kind of top are you using on the tank? Are there ventilation spots in it?
For what it's worth, when purchasing thermometers, I check all of them on the shelf to see if they show different temps. ( Often times they do :^s ) I choose one that is similar to the majority. (y)
 
Back
Top Bottom