Need some help from Physics guys regarding external temperature vs Tank temp!

  • Get the NEW AquariaCentral iOS app --> http://itunes.apple.com/app/id1227181058 // Android version will be out soon!

LMOUTHBASS

My hypocrisy goes only so far
Jun 17, 2003
1,326
1
38
Boston , MA
Visit site
Real Name
Mark
Hey guys - need some help from people that know more than I about this!

So I have an indoor NON-heated porch. I live in the Boston area so it gets cold in the winter. Planning ahead now... At the moment I have a 36 gallon and a 46 gallon that I'm setting up in there. I've made the whole porch like a jungle theme with huge tropical plants and the two tanks caddy cornered opposite each other with some lanterns hanging up with candles in them and such... looks pretty cool. Off topic but anyhow I'm wondering if I'll have to move this all inside once it gets cold?

If I keep the tanks warm at about 80-87 degrees in the winter, will they stay warm against the unheated porch? Also, would the opposing external cold air vs the internal warm water cause the glass to shatter?

I'm not a physics guy so I want to work through this now long in advance! I suppose my other options would be to set up space heaters or leave the door to the porch open allowing heat from the house to flow out there... but that'll jack the heating bill up and space heaters make me feel uneasy

Thoughts?
 

dougall

...
Mar 29, 2005
3,480
900
120
Personally, if the air temperature in the porch will get to around freezing, then you will need to keep the water warm somehow.

typically heaters are designed to raise the temperature of water maybe 10 degrees above ambient. so from freezing you'd be looking to raise the temp ~50 degrees, so 5 heaters for an appropriately sized tank each, and expect them to be running constantly.

also bear in mind that if the power fails, and you're without power for long enough for the water to freeze, the pressure exerted by the expanding ice may well break the seams of your aquarium, and once it defrosts you may have other problems.

There's also always the chance that you can insulate the tanks with styrofoam and such, it might be more difficult if the tanks are bowfronts, and based on the numbers I think they might be.

in a nutshell, I'd personally break down the tanks for the winter, and use another couple of tanks in your home, or move these tanks. There's too much risk for me personally to take the chance.
 

spencerguy1

I dont do Tuesdays.
Jul 19, 2010
1,619
0
0
25
Illinois
Real Name
Spencer
The cold air outside is going to draw heat from your tank, but since you are constantly heating the tank that will only lower the tank temperature a feww degrees. Hence you will need to turn up your heater a bit.

Personally, the situation you would be setting up would be so delicate that I don't think it would be worth the risk/effort. So much could go wrong. Freezing temperatures could break the glass, changes in outside temperature could fling your water temp all around, your water would evaporate much faster, etc. I don't think it would be worth the risk of equipment damage and fish damage, not to mention you would have to constantly be mantaining the tank. You could place a couple smaller tanks out on the porch and take them down when winter hits, but otherwise things aren't going to turn out well.

I live an hour north of Chicago, so judging by how cold our winters get and how random winter temperatures are up here, I wouldn't do it. Good luck though whichever direction you choose to take.
 

LMOUTHBASS

My hypocrisy goes only so far
Jun 17, 2003
1,326
1
38
Boston , MA
Visit site
Real Name
Mark
Good points guys. Thinking more into it I think I have my answer. Fortunately, I have some space indoors that I can move the tanks to once it cools for the season since they're both under 50 gallons it won't be too big of a deal.
 

Byron Amazonas

AC Members
Jul 22, 2013
986
2
18
73
Pitt Meadows (within Greater Vancouver, BC) Canada
Real Name
Byron
I agree this is not going to work, assuming the ambient temperature of the room lowers significantly. I would like to pick up on one point though, to correct. And that has to do with the tank heaters maintaining a warm temperature in a cold room. They will not do this if the difference is beyond about 10-12 degrees. And if they are constantly "on" in the attempt, they will fail before long.

Aquarium heaters are intended to function when the intended tank temperature is no higher than 10-12 degrees above the ambient room temperature. Most will say this in the instructions. They are not meant to be on continually. And having more of them is in this case not going to have much effect. You might be surprised just how much heat passes from the warmer water into the cooler air, and the colder it is the more this accelerates.

This is the idea behind double and triple glazing windows in cold climates. The air space between the glass acts as insulation. But without this, as in single-glazed windows, the amount of heat/cold transfer is incredible. Some of you might be "old" enough to have experienced single-glazed windows in your house. When I moved into my home, in 2000, it had the original single-glazed windows. Winter arrived, and it does not get all that cold here in Vancouver, rarely below freezing. But the cold draughts that blew in through the glass--yes, right through the glass, not through openings in the casement--was sufficient to keep the house cold even with the furnace cranked up. I replaced the windows the following Spring, and for the past 14 years have had a nice warm home on cold days. Previously, if you held a lighted candle in front of the single-glaze window, the air movement would actually cause the candle flame to flicker. And that was not wind, just the force of cold entering the warmer house through the glass. I wondered why previous owners didn't replace the windows, as their heating bills must have been through the roof, unless they sat around wrapped in blankets.

Back to your situation, it might be worth insulating the porch, as it sounds like a very nice "tropical/fish room." I have something of a similar situation, in that my fish tanks are in the enclosed carport which was insulated by the previous owner who did the work, but the room gets very cold in the winter as it is on the end of a rancher and the only door is off the mudroom. I have a baseboard heater that is turned on to 70F all winter, day and night, in order to keep the room at 70F, which means the aquarium heaters can then reasonably heat the tanks to 77-78F.

Byron.
 
Last edited:
zoomed.com
hikariusa.com
aqaimports.com
Store