Halibut

I was wondering if anyone new of an insulation to use on an aquarium that is on an outside wall(it cannot be moved to a better wall because thier isnt one right now). With the temp fluctuations right now I have a feeling my heater might be ok but just cant keep up with that outside wall leeching out the heat at night. A friend and I were talking and he mentioned a thin foam insulation that would stick to the back of the tank. I have the vistherm stealth's on order but my thinking is this might be a bigger issue at this point.

Dino

Foam insulation board would be a good idea.
It can even be attached to the back of the tank.
Looks for the one that has the highest R rating.
Saddly, it usually only comes in 4 by 6 foot sheets.

susitna-flower

The blue board would even look "aquatic" . I have my big tank on an outside wall, and worry about the same thing....though I guess not as much as I should, I've never done anything like insulate....Good thinking...

Tavel

I'm actually thinking mylar here. I would think the heat loss would be mainly radiant, not conductive because glass and air are both pretty good insulators. Just a thought.

Halibut

I'm trying some things temporarily until I get it ironed out and get my visitherm in the tank. Hoping this works because it'll be easy to doubleside tape the insulation to the black aquarium backing I have. Right now I just have the foam insulation from home depot, mylar may work as well I'll have to look into that this upcoming week.

sirdarksol

A combination of mylar and the board would be good. Glass itself actually isn't all that great of an insulator. Why it is usually used in insulation is because it can be used to trap air (or better, vacuum), which, as Tavel said, is a great insulator.
The foam board will help keep the cold air from the wall from coming into contact with the glass, and the mylar (on the inside of the board) would help feed heat back into the tank. If you want a darker background, you can splurge and get some of the darker mylar. Not as reflective, but will look better, probably.
Another thought would be to hang something on the wall behind the tank (a tapestry, of sorts). This was a common tactic in earlier ages when a poorly-insulated wall was in a commonly used area. It provided an extra measure of insulation.

All just ideas. Good luck with your heating situation.