Lighting causing excessive heat

[bpeitzke]

We've finally got our new 65-gal FOWLR tank set up. I'd been running the lights from 8:00am to 11:00pm, but found that the temperature gets up into the mid-83 degree range, even with the heater's thermostat set at 80. I have observed that the temp goes up when the lights are on and down when they are off. As an interim measure I've reset the lights to run from 6:00pm to 11:00pm, and I'll keep an eye on the temperatures.

Actually, I'm not sure these temperatures are excessive. I just reread an article by Dr. Ronald Shimek, "Natural Reef Salinities and Temperatures", in which he cites average sea temperatures in the Indo-Pacific region, in the 83-84 degree fahrenheith range. I would appreciate feedback on optimal temperatures and salinities. (We've been keeping the salinity in the range of 1.022 - 1.025.)

One thing I'm considering is to get another timer and run only one of our PC flourescent bulbs during the day, running both only during the prime evening hours when we're there to enjoy the tank.

I'm looking for suggestions on how to best manage temperature with this setup. Here are my tank parameters:

65-gal tall acrylic tank (23.5" height)
Current USA Dual Satellite Compact Fluorescent 30" 130w with moonlight LED's (very cool)
CPR Cyclone BAK-PAK2 Bio-Filter protein skimmer
Finnex 200w Digital Titanium Heater
2 x MaxiJet 1200 PH's
Hydor Koralia 2 circulation pump (1)
50 lb fine-grain sand from LFS (allegedly not aragonite but what they use in their display tanks)
Lots of Fiji LR (bought over time, thus don't know total weight, but tank is full of it)

Fish:
- Spotted green puffer, 6" (1)
- Yellow Tang, 4" (1)
- Zebra Damsel, 3" (1)
- Coral Beauty, 3.5" (1)

We'd like to get a couple of more fish after we're confident of a stable environment. That's a subject for another post. The tank is beautiful. I'll try to post some pictures soon.

Grateful for any advice

Bob Peitzke
Pacific Palisades, CA

 

[Sadielynn]

Temp stability is key in yor tank ,83* is not that bad but it is stability that you wnat you dont want swings of more than 1-2 degrees in a 24 hour period ..Why not try to run your lights in the afternoon say acitinic lights from 2pm till 3pm then your day lights with acitinic from 3 till 10pm and acitinics from 10till 11 pm ...
so your lights would look like this
acitinic on 2pm
daylights on 3 pm (acitinics once on will remain on till final time)
day lights off 10 pm
acitinc off 11 pm
this would give you 9 hours of show time and help retard any undesiarable algeas from forming ...
If your temps are still of concern try runnign a fan across the top of the tank of course you will have more evap and need to top off more which can be negated with the use of an ATO (Auto Top Off) device ...
To also help with temps look into a ReefKeeper 2 this will turn the fans off and on when the temps get to what you determine to be to hot . It will also shut off the heater if it is too hot and in worse case senario turn the lights off ... This will automate your lights temp and your fans ect ... this is what we got for ours when we had a heater malfunction and the tank heated to 105* ...

 

[melosu58]

Sadielynn hit it on the nose. Stability, Stability and Stability.

 

[bpeitzke]

Thanks

Thanks for the advice, SadieLynn.

Our light fixture has built-in fans at each end, and the back of the hood is open, but the fans don't make much airflow, and I do suspect that a supplemental fan could extract more heat.

I like your suggestion for a partial lighting schedule - I'm going to get another timer and set that up.

But I think the best thing you gave me was that stability is important, and 83 degrees is not necessarily too high.

Regards,

- Bob

 

[melosu58]

You dont have a glass hood do you?

 

[roka64]

I run a fan with my lights. But stability is best.

 

[Ziggy953]

I was going to ask if you had glass tops too. With 130w pc light you shouldn't be generating that much heat. I have 678w on my 72 and my temp doesn't swing like that. Do you have any holes drilled in the top of the canopy? If you are having that much trouble with heat try using a holesaw and put some hold in the top of canopy to let heat out.

 

[Kurt_Nelson]

I'm going to take a giant step back and ask how you're measuring your temperature?

Also... what is your high/low temps? You say that you're getting around 83 as a high, but I'm missing what your low is. What your heater thermostat is set at (in degrees) really doesn't matter.

If your temp swing isn't that big (like a degree or so), it's just a matter of turning your heater thermostat down.

 

[bpeitzke]

Measuring my tank temperature

I have a digital thermometer that sticks on the outside of the tank, with a probe on a cable that sticks to the inside of the tank. My Finnex Titanium heater has a remote control unit that hangs outside the tank, with which I can read temp and set thermostat. The temps recorded by the Finnex and the other thermometer don't agree - they differ by about one degree IIRC.

But the tank temp was going above the thermostat setting of the heater, even when I'd set it down to 80, it was spiking over 83 after hours of lights on. So it was definitely the heat from the lights that was jacking up the temp.

I've increased my heater thermostat to back to 82 (reads 81 on other thermometer), and cut back my lights-on hours to six. Now I'm seeing only about one degree variation. I think I'm OK.

Thanks.

 

[roka64]

Both your heater and temp probe have a +/- degree of error. They should say in the instructions.

 

[ccCapt]

I agree with the stability and also agree 83 is not bad. What I don't understand is how a 65g tank is getting overheated by 130w pc lights. I run 350w (2x175) of MH for 8 hrs/day and 160w no flourescent (4x40) for 12 hrs/day and I have no problems with temp. PC's run way cooler than MH's. Something just doesn't seem right. Can it possibly be one of your pumps is running hot?

 

[melosu58]

You dont have a glass hood do you?

???

 

[Kurt_Nelson]

Agree with cccapt... and that's why I was asking more questions.

I have 196W of PC lighting on my 46g, on for 10 hrs a day, WITH kind of a glass top (it's open somewhat for ventilation), and my tank temp doesn't vary more than 1.5 degrees this time of year. Low temp in the morning is 77.2 to 77.8 and the highest temp at lights off is 78.4 to 78.8. And I'm not even using a temp controller... just 2x 100W Visitherm Deluxe heaters.

 

[cmor1701d]

Having gone through this recently my solution was adding a fan time to come on 15 minutes after my MH lights come on and go off just after those lights do.

I also found that my titanium heater was off by 2+ degrees. I had a cheap plastic stick on (suction cup) thermometer that was reading a few degrees higher than the digital display of the heater. My digital BigTemp was broken and while waiting for its replacement I bought a lab grade thermometer. That agreed with my cheap plastic thermometer. Hard to beat a cheap calibrated thermometer.