Fluctuating Water Temperature

[CPQ]

sorry if this is a stupid question but its been bugging me for a while.

I've got a 4ft by 1 ft by 16 inch tank with a 300w heater. the heater sits next to the filter (power filter - cant remember for the life of me the make) to make sure theres good water flow around the heater and is kept at about 25/26 C. But the water temperature fluctuates everyday. I'm pretty sure this is due to the light - i can feel the heat given off by the light and I'm sure this must be heating up the water.

First thing in the morning the temp will be about 24 (sometimes 23!! which worries me) and will heat up throughout the day to about 26 then drop to 23/4 again overnight. Like i say, I'm certain this is due to the light (makes sense - light on - water heats up, light off - water cools down). BUT i wondered whether this could be bad for the fish? and if so, if there's anything i can do to keeo the temperature more constant??

Thanks

 

[merry78]

i am no expert, but until someone comes along who knows enough to answer you definitively, i would guess that any fish who are not deep water fish should easily cope with daily fluctuations of a few degrees or so, as i imagine they would get that or more in the wild anyway when the sun rises/sets.

 

[tansdale]

i am no expert, but until someone comes along who knows enough to answer you definitively, i would guess that any fish who are not deep water fish should easily cope with daily fluctuations of a few degrees or so, as i imagine they would get that or more in the wild anyway when the sun rises/sets.

I agree. However I suspect that this temperature variation is not uniform throughout the tank, and is probably a result of the placement of the thermometer and the water circulation around it.

 

[CPQ]

Yeah - my logic was that fluctuations must occur in the wild!

tansdale - the heater is next to the filter so as to get the most water circulation and the thermometer is at the other end of the tank (so i know all the water's getting heated not just that nearest the heater). i figured that was the best way to do it?

so do you reckon it's fine for me to leave things as they are and just keep an eye on it?

Thanks

 

[SuperColey1]

Its not a problem at all.

High light tanks like mine mean that the lights can send the tank up by 3ºC.

My tank hit 31ºC earlier this summer.

I do cold water changes too and this is 50% water change as I use EI method which brings the temp from circa 26ºC to between 20ºC and 22ºC.

This doesnt cause the fish any problems and it is well known that doing a cold water change often gets fish like catfish into spawning mood.

Andy

 

[juiced1300]

I've always kept my tanks in areas of the house that get a lot of light, though not something i cant control, I can always control this with window blinds etc. I've seen my tank temp go up a bit during the mid day and then back to its normal temp setting. I would be more concerned with the coldest the tank gets, if the temp is not being held during the night it could be your heater isnt up to task. I personally rather have two heaters than one big one. I have them set up on either sides of the tank so that cold spots are minimal if there at all. I've moved my thermomitor around the tank, high in one corner, to bottom of another corner to see if theres temp differences and have found none. But I also keep my tank under a lot of filtration and have airstones etc so theres a lot of movement (nothing crazy of course).
Like everything else in life, just use a little common sense and judge things for yourself. If you do decide to split your heaters, spend a little extra and get a quality heater(s), it saves a lot of stress down the road!