"Tasslehoff" wrote in message
...
I'm thinking of getting the dupla thermik coils for my new 4x2. The temp
around here is 60F and was just wondering what I could use to stick them
down on the tank bottom. Could I use silicone and have small 1cm plastic
tubing of some sort with the coils running through them each couple of
feet
. These coils are only designed to heat the substrate so would the
heating
coils melt this sort of setup? How deep should the coils be positioned
in
the substrate, right on the bottom/middle? Any other options? Ta.



FWIW, I have heard quite negative things, both from here and from other
hobbyists, about UG heaters. I have heard *many* stories about ppl setting
up very large tanks, then having the coils quit. Replacing them is obviously
not an option. I considered it when setting up my 45 planted, but decided
that the risk of having to replace it was worse than hiding a submersible
heater. I have mine positioned behind a ph with prefilter, you can't even
see it unless you look from the side, and the ph itself will be obscured by
cabomba very soon.
As far as your question about melting the silicone, with the constant
water contact, the temperature wouldn't ever (imo) get high enough to melt
it.
In short, if you're stuck on substrate heating, I'd do some research and
get the best quality coils you can find, and good luck to you!