An external thermometer (color strip things) will read low when the water is warmer than the air and high when the opposite. They can be off by 6 degrees easily on glass tanks.
Bottom resting thermometers will read the temp of the bottom of the tank, if you don't have a filter circulating the water then the heater itself is doing so. Generally if you don't want to use a filter but will use an air-stone or air-toy that will circulate the water as well.
I get both a bottom resting AND a suction cup thermometer then just take the suction cup off and replace it with a rubber band so it won't make noise against the side of the tank.
If the heater alone is stirring the water, try angling it about 20° it should work better. Keep in mind its going to be fighting the house air so if you've got air-flow around the tank the heater will have to work harder.
Remember to stir the water down by any rocks or substrate you have as well, so he doesn't suddenly swim into really cold water.
i am using a glass thermometer that suctions to the inside of the tank...
i do have an air stone, that i turn on a couple times a day. i don't leave it on, because it seems to create more current than i think he would like for an extended period.
the heater isn't stirring the water at all, as in, the heater causes no current at all. the water is completely still as long as the air stone is off.
he doesn't have any rocks in his tank at the moment, as i am treating him for slight fin rot. :(
also, this morning, the thermometer reads the same, about 72 it looks like... also, the red light on the heater has never gone off, or turned green or anything. i thought that meant it hadn't reached it's max heat (78 degrees).
should i get another thermometer? another heater? i'm not sure if i've got this right.
thanks for your help.
Last edited by orphansparrow; 05-02-2011 at 10:24 AM.
Maybe try a 25 Watt if the 10Watt isn't heating efficiently. I just did a product search on Marina brand for 10-50Watt heaters and their rating's aren't the greatest. Maybe take back the one you got and tell them it wasn't working and if they give you in-store credit or your money back look for something that's 25Watt's perhaps with an adjustable temperature knob.
cyerryn - do you think a 25 watt is safe for a 2 gallon??
by the way, the red light on the heater finally went off! that is supposed to mean that the heater has reached it's "optimum" temp. by my thermometer thats about 75 degrees. and today during my water change, i tested my thermometer and it does work...
and, my betta for the first time made a bubble nest today!! so that must mean he feels better in the warmer water. aww...
I don't see how a 25Watt would be bad for a 2gal especially if it's adjustable. If what you're using is working, then scrap my idea. I was under the impression that it wasn't putting the temp. out where it should be. I was told a good rule of thumb is 5Watt's per gal, but I use a 75Watt for my 10gal and its perfectly fine. A nice 82F temp in the tank and Sazzer actually sleeps right between the glass and the heater. Silly fishy! Guess he likes it toasty. Glad yours is working fine and that your fishy made a bubble nest!! Bubble nests are awesome to see. I have a QT 1gal bowl that is unfortunately unheated atm and stays at around 73-75F and he seems really happy in there and makes large bubble nests. So did my other two boys that were in it before him... but it really looks that they seem to thrive in temp. around 78-82F. Just something for you to think about for your boy in the future. :P
you are right, the it isn't putting the temperature where it should be, it's supposed to go up to 78...today it looks as though its about up to 75, maybe a bit lower...but, for now i'll just stick with this one i think, because it will be summer here soon, and i think it will be warmer anyway...i don't know. im a bit undecided, because i would like the temp to be higher, but we'll see. ^_^ thank you so much for your opinions & advice!
It's hard to find a heater that heats to the exact temperature it's set to. Mine is off about 3-4F so I keep it at 86F and it read's 82/83F near the heater, and 80F furthest from the heater. It's trying to keep the water at a stable warm temperature that you aim for. If you can keep the water at 75-78F during this summer then I don't see a problem with it, though some may beg to differ to my opinion. I'd definitely get a different heater after summer though.