Styrofoam and Heat Mat?

[John]

Hello.

I am just setting up an aquarium. It is around 25 gallons
(30x15x15"). I am going to have it mainly as a planted freshwater
tank. I have a heat mat for substrate heating but wondered whether
it matters if it is under or above the styrofoam?

It has a small bump that sticks out a bit where the power cable goes
into it so I will have problems having this between the aquarium and
styrofoam. I could have it underneath the foam and it would stick out
a tiny bit, or I could have it between two layers of styrofoam with a
bit cut out to allow for the bump, and then have the aquarium on top?

Would it cause problems though if the styrofoam is getting heated up?
I believe the heat mat is around 38watts. I am just cautious of what
is best to do.

Anyone else have a heat mat and styrofoam? And how do you get round
that problem?

John

[Sue]

A heat mat won't work if its below the styrofoam!

I would make a depression in the styrofoam base for the connector if I used
one of these but I've never felt them worth the hassle.