Termperature help ASAP

[n00b mariner]

Just added two powerheads for flow and the temperature is getting critical......Ive turned one off and turned thermostat on heater to lowest but its still @ 26 C..............How can i control it....its pretty cold here in the uk at the mo (0C) and dont want to wake up in the mornin to either a freezing cold tank or red hot one ........what do I do?:eek2:

[Yellow Hat]

I don't know what size tank you have, but mine is a 46 gal Bowfront. Everyone told me I needed a "chiller" so that's what I bought. It is a 1/10 horsepower chiller and even though it's a cheap one it runs pretty quiet.

[Big Amish]

So that I understand you correctly, your temprature is dropping since adding the powerheads? How powerful is your aquarium heater in watts? How many gallons of water do you have in your system? Is your thermometer next to your aquarium heater, or on the other side of the tank?

It sounds to me like your tank has been running cool already, and these powerheads are just exposing the fact by circulating more water around your thermometer. A tank with low circulation will develop cool and hot spots. Check to make sure your aquarium heater is powerful enough to warm your entire tank. If not, add a second heater. ( Don't just replace the current one with a bigger one. Two smaller heaters are safer in case one breaks down. )

[ReeferAl]

What do you consider "getting critical"? As long as it stays below about 29C that is fine. Even a bit higher occassionally is ok. 26C is still a fine temp for a reef tank. Is your heater calibrated? It shouldn't be going on if the tank temp rises due to the pumps and lights but should only come back on if the temp later falls. I would leave the heater set to about 24C as that is about as low as you would want it to fall.
If you find it is still getting too high you could try getting an "Iceprobe" thermoelectric chiller if you wanted . That is about the largest tank it would work on and then it would only cool it a few degrees.
Or you could try setting up a small fan to blow across the water surface and put it on the same timer with the lights. That can be very effective if you have an open top (no glass cover). If you have a sump that can also be a good place to put the fan.
Allen

[n00b mariner]

Heater being used is a fluval 150W. Thermometer isnt fixed and the temp used to read a constant 25C. After fitting two powerheads for EXTRA flow temp shot up to 28C. Like i sed i turned one Powerhead off and turned heater right down but want to stabilise properly with low ambient temperature and all equipment running. Any ideas?

[n00b mariner]

30g tank, no sump and no open top:confused:

[mikeatjac]

If you aim one of the pumps to disturb the water surface that will help cool the tank. A clip on fan would help too.

[mikeatjac]

Do you need the tank cover?