Heaters, lighting and temperature

[bogusmove]

I wonder if anyone can explain this problem I have.

I seem to have alot of trouble keeping the temperature right. It goes up during the day and down at night. I'm trying to keep my aquarium at 86 dF at the moment as i'm trying to kill ich, but if I adjust the heaters to try and achieve this (by setting them to about 81 dF) I find that the temperature can drop to 84 dF during the night!

I have 2 * 200W heaters which is more than enough power, and circulation is good, and I can keep the temperature 86 to 87 during the night by having the heaters set to 86 in fact, so it seems to be working fine in this case, but if I leave it like that during the day it will shoot up to 88 or more!

I would blame the lighting for heating the water, but I can see that as the temperature creeps up the heaters (both of them) are still coming on, so unless lighting can fool a heater into thinking it is cooler than it is I don't get it.

I get the same problem at lower temperatures too but a bit less so.

Anyone have a clue what might be going on?

 

[thecichlidaddict]

All I can tell you is that a temperature swing of 2° at night is nothing for you to worry about

 

[Mako]

How long do you wait before you adjust the heater?

 

[bogusmove]

temperature swing of 2° at night

Ok

How long do you wait before you adjust the heater?

You mean in the morning, adjust it down? Usually midday ish... or before, temp can start to run a bit high by midday though...

 

[Dubby]

All I can tell you is that a temperature swing of 2° at night is nothing for you to worry about

I'll second that. In the tropics it would be perfectly natural for temperature swings between day & night (sometimes upto 10-15deg)