How Hot Is Too Hot?

[Mola Mola]

Hi,
I'm having problems with my heater (or thermometer) at the moment, and don't seem to be able to get the temperature of the tank below 31C (assuming the thermometer is correct).

I'm currently a couple of days into a fishless cycle. Is 31C too hot for an efficient fishless cycle, and is it too hot once I eventually put fish in?

Any advice would be very appreciated.

 

[StandbySetting]

31 is great, it will increase the rate of bacteria reproduction.

 

[Mola Mola]

31 is great, it will increase the rate of bacteria reproduction.

Thanks. I was hoping that was the case. Certainly I seem to be getting a bit of ammonia and nitrite conversion.

Is it too hot for fish though?

If it isn't, I might just stop worrying about the heater and plan to leave the tank at 31C.

 

[StandbySetting]

It's too hot of the majority of fish, what temperature have you set your heater at? Most aren't that accurate so a bit of trial and error is needed, also how long are your lights on for? What type of thermometer are you using?

 

[KittyKat]

31 C is far too hot for fish, but is great for a cycle.

What is your air temperature and what sort of thermometer are you using? Does the heater have a red light which goes on when it is working and off when it is not? Is this on all the time? What happens if you turn the temperature setting well down?

 

[Mola Mola]

31 C is far too hot for fish, but is great for a cycle.

What is your air temperature and what sort of thermometer are you using? Does the heater have a red light which goes on when it is working and off when it is not? Is this on all the time? What happens if you turn the temperature setting well down?

The heater is currently set to 26C but is still switching itself on, even though the thermometer is reading 31C. It is not on all the time, but comes on frequently, suggesting that it is trying to maintain the temperature.

I exchanged an identical heater yesterday that was doing the same thing at 24C. The guy in the fish shop checked it, and confirmed that it was coming on, even when turned down very low.

I suppose that either the thermometer is wrong, or it could be a bad batch of heaters.

In the morning I am going to go and pick up another thermometer to get a second reading, and then take the heater back if the new thermometer confirms that the tank is at 31C.

I'll get an air temperature reading and post that here, but I don't think it is very high and, as I mentioned, the problem is really that the heater still turns itself on, even when set low.

 

[StandbySetting]

How long are your lights on for each day? And what type are they.

Try turning the heater down to 21 and see if it maintains a more suitable temperature.

Most heaters are out by several degrees.

 

[Mola Mola]

How long are your lights on for each day? And what type are they.

Try turning the heater down to 21 and see if it maintains a more suitable temperature.

Most heaters are out by several degrees.

I don't currently have the lights on. Do I need them on when doing the fishless cycle?

I will turn it down to 21, as you suggest, although I have a feeling it will still stay at 31. Whatever I set it to, it seems to want to keep it at 31!

 

[StandbySetting]

No, you don't need the lights on, what's the ambient temperature of the room?

 

[Mola Mola]

what's the ambient temperature of the room?

Seems to be 20C.

 

[StandbySetting]

Has that been measured? Or have you just estimated it?

 

[Mola Mola]

Has that been measured? Or have you just estimated it?

I used the tank thermometer to measure it, just left it out of the tank for 10 minutes.

 

[Curiosity101]

Most heaters are out by several degrees.

That used to be true but isn't anymore. If you buy a new 'branded' heater that is the correct size then they're often pretty accurate.


@Mola Mola - I have quite a few older ones and I accept them being 2-3C out... but if yours is at least 5C out (and is brand new) then I'd say it's a bad batch. Perhaps you could order one online from a different store (so hopefully a completely different batch) and return your current one for a refund when the new one arrives? Just out of interest what brand/size is it?

 

[StandbySetting]

Those that use bi-metallic strips can be several degrees out still, the digital heaters are those that are pretty accurate, though I do agree that 5 degrees is rather extreme.

OP - what model heater do you own? If you do return it can you swap it for a different brand?

 

[waterdrop]

Did you calibrate the heater? Many (well, some, I have no idea which do and which don't) heaters have a variable adjustment separating whatever is giving you the numerical feedback versus the actual rheostat that is adjusting the "set point" (which you determine by observing when the light goes on or of as Kat mentioned.)

For instance, a common design is to have the post that extends from the rheostat be capped with a knob with temperature degree numbers on it. The user then rotates the knob so that the the desired temperature number matches a pointer that is not on the knob. The bit that is often overlooked is that the "cap" of the knob can be separately adjusted to "calibrate" where the numbers are relative to the actual post part. (Remember, this is just an example - there are different designs for different heaters.)

Anyway, the "calibration" of course requires that the actual "taken as correct" temperature come of a separate thermometer: one reads the thermometer and turns the rheostat just to the point of the heater lamp going on or off and then separately adjusts the "cap" to the temperature number that was taken from the thermometer. Ideally the manufacturer should instruct you in this process but sometimes this is missed.

Apologies for the above detail as you likely know or have done all this already but I just thought I'd mention it. Any sort of warm environment in the 28, 29, 30, 31 C range is going to be more encouraging to the autotrophic bacteria than if the water was down at fishkeeping temperatures or below. The bacteria grow a little faster at the warmer temperatures. Discussions with scientists who grow these things seem to put the best compromise temperature at 29C/84F as the optimals are a little different for the two species.

~~waterdrop~~