DIY background - silicone and heater ?s

[ownedbycats]

I really want to do a background for my tank out of styrofoam. I've got GE type 1 for windows and doors, and the styrofoam and am designing my background. I read somewhere that heaters shouldn't be near anything silicone'd because the heat weakens silicone. Is this true?
If it is, how far away from the silicone is safe?
Does this also apply to where the glass of my tank is sealed?
Does putting your heater behind the styrofoam prevent it from heating the tank properly if you leave lots of holes for the water to flow through?

 

[stevenhman]

As long as the heater has a good flow of water across it there shouldn't be any problems. If it still worries you, leave room enough to remove the heater just in case while the tank is cycling. This should be a nice test period to see how things work out.

As for foam/silicone damage... I doubt it. The heater shouldn't get hot enough to do any damage. If you are using a canister filter or sump you can always just use an inline heater.