Suddenly hot...

[kmatysek]

We have a 2 1/2 year-old set up (90g) which is suddenly running hot (82 degrees). We keep it at 75 and I have never had a problem. (Our house is air-conditioned and is at 75 all the time in the summer, so that's not it.) I unplugged the heater last night (it's a 'Visi-therm') and I'm waiting for the temp. to come down (it's at 80 after 17 hours).
My question is: why did this happen?
Will a heater fail by heating too much (I assumed it would just stop altogether). I haven't had to adjust the setting on the heater in these 2 1/2 years.
Could our lights have caused a spike? I normally check the temp. in the AM to avoid fluctuation from the lights, but I thought it felt unusually warm when I went to feed them last night. Still, it was 80 this morning, so this isn't normal fluctuation from lights. We've been using the same light fixture and same brand of bulb all this time, but the bulbs were over-due for replacing (in fact the replacements arrived yesterday so I just did that). Again, I would think old bulbs would be cooler, not hotter.
Is there anything else that could cause the temperature to rise (other than room temp, heater or lights)???
Thanks for any advice...

 

[saltyrich]

Relax. You are not in a danger zone yet. In fact, search some older threads about reef temps. Many recommend temps in the 80-82 range. My tank fluctuates daily between 79-82 degrees without any problems. As far as the heater goes, I'd try switching to an EBO Jager. I think that they are the best quality product for the money. It was recommended to me by some sharks on this board. The cause for the increase is a mystery to me at this point. I would not worry about the temp enless it goes above 85.

 

[nm reef]

Actually 82 is not that serious ....a lot of us keep our systems in the 80-82 range. It is possible that your heater malfunctioned...I had a cheap one stick on me...temp rose above 84 and it cost me dearly(I'd also suggest you replace yours with Ebo Jager...they are quality heaters). Another source of heat is power heads....have you added any....or do you have any that need cleaning/maintenance?
A remedy for temp swings is to place a fan so that a breeze blows across the water surface...it will increase evaporation slightly...but it does cool the temp a bit also.

 

[kmatysek]

saltyrich-
Thanks for the heater recommendation - I'll check it out.
Yea, I should have said that I'm not worried about it being 82 degrees, but I am worried that I don't know why it suddenly went up and want to be sure I've eliminated the culprit. Hoping someone's been there...

 

[kmatysek]

NM Reef-
Aw, I think you're on to something. I know I haven't cleaned the powerheads in a little while. Darn, why didn't I think of that (and I call myself an electrical engineer )! It's also good to know that a heater can fail 'open'. Yes, I was worried that stuff would cook before I caught it.
Thanks to both of you for your tips!