min and max water temperature

[bettaninja]

Hi,

We are currently setting up a 155L tank and it has a 200W heater installed. It has no fish in it yet, but it is setup and running with a few plants. We have been leaving the lights on for about 12 hours a day. We plan on keeping tropical fish (corys, danios, gouramis, bristlenose and upside down catfish).

We turned on the heater about 1 week ago set to 25.5C and the tank temp reached 26.3C. So we turned the heater down to 24C but the water temp is still hovering around 27C. We have 2 thermometers, one digital, one floating (we bought the floating one because we wanted to verify the reading from the digital as the temp seemed quite high).

The room temp is between 25 and 29C, which is about average for this time of year (Sydney, Australia). We are planning on getting air-conditioning later down the track.

The min water temp in the tank today was 26.3C and the max was 27.8C. Is this too much of a fluctuation?

What min and max temp should we aim for and how do we cool down the water in the tank to bring the temperature down if it is too high?

thanks!

 

[The-Wolf]

temperature fluctuations of more than 2 degrees may cause a problem.
As yours is just over one then I can't see any problems so far.

 

[bettaninja]

We don't have any fish in the tank yet, although we do have plants. We were trying to experiment with the water temperature.

We have an AquaOne AR850. On 10/01/2005 we took the filter covers off, hoping some air over the filtered water would cool the tank down. We also floated some ice packs in sealed bags in the tank. The temp was 27.8C that night. The next morning, it went down to 25.3C. We've been monitoring in everyday, and noting what has been done to the tank (eg, lights on, filter covers off, room blinds closed etc).

A day later, we noted the following which I thought was good because it didn't fluctuate by more than 2 degC:
Internal water temp:
current 25.8C Min 25.6C Max 26.1C
Outside room temp:
current 25.3C Min 25.2C Max 25.9C

But yesterday (really hot day - I think 32C to 36C forecast), we had these readings:
Internal water temp:
current 27.6C Min 25.8C Max 27.6C
Outside room temp:
current 26.3C Min 25.3C Max 26.3C

During the day we had left the filter covers on, lights on in the tank, closed the room doors and the window blinds (this keeps the room cooler as we have floor to ceiling windows that get a lot of sun).

So it looked like the water temp increased by 2C but the outside temp only went up by 1C. I think it is because the lights in the tank put out a lot of heat. Our sensor is all the way down near the gravel and the temps have been verified by a secondary floating thermometer that is situated next to the uptake of the powerhead going to the filter.

Today is another scorcher, with temps soaring to 39C. I'm worried about how to maintain the temperature when we do get fish. And I'm worried about the plants. Would they be affected by the ice packs?

We are thinking of getting a computer fan and mounting it above the filter, removing the filter covers and getting the air to blow on top where the water flows across. Would this kill the beneficial bacteria in the filter?

Any comments would be appreciated! Thanks!

 

[gadazobe]

Gadual increase in the water temperature shouldn't affect the fish. They get stressed when the differences are sudden. The fan across the water is a good idea but I don't understand why you have to take of the filter cover, could you please explain more fully.

Fish are suprisingly resiliant to high temperatures - they are after all, tropical. My water temperature has reached 30 C with no ill effects and I brought it down gradually with ice packs.

 

[bettaninja]

thanks for the reply.

I'll try to describe the filter as best as I can. I don't have a picture at the moment but will try to get one tonight.

I have an Aqua One AR850, which is an all in one unit that has tank, filter and light. The filter is housed on top of the tank. There is a powerhead that sucks water from the tank through a hard tube. This tube goes straight up to the filter housing and has a right angle bend. It extends along the length of the housing, has holes for water to come out and pour straight onto the filter medium. The water gets filtered and runs back down through a hole back into the tank. The filter housing has 3 flat plastic covers running end to end.

Regarding the ice: I didn't know you could float ice in the water (in a snap lock bag) when there is fish in the tank. I thought it would shock the fish.

 

[Mr Miagi]

Do you have sufficient water flow around the heater? It (the heater) may have a busted internal gauge, in which case, a replacement will do the job. Goodluck

 

[freddyk]

Just be careful how much ice you use, too much could cause a sharp drop, but just enough will cool it helpfully.

Fluctuations in temperature will not harm the fish in any way. Consider these two facts. The first: in the wild the temperature is by no means stable, and in some places can change quite rapidly. The second: When we buy a fish we float the bag to adjust temperature. The bag rises or drops to the temp. of the tank withing about 10 minutes or so. The idea is not to drop the fish from one temp directly into another.