Substrate Heating Alternatives

I've been on this list  for quite some time and look forward to the
daily discussions.  Just as many of you, I've learned more from this
list than anywhere else.  My thanks to the many of you that share
your expertise (George, Karen, Paul, Kevin, just to name a few) and
to those that maintain the list.  I've been able to incorporate many 
of the ideas from the list in my tanks.  I'm curious, how many 
subscribers to this list are they?

I have a question that I don't believe has been addressed.  I've yet
to see some economical substrate heating system proposed.  I don't
feel comfortable enough trying to engineer some electrical and wiring
system (one proposal from the list) to place in the tank and can't
afford the Dupla system.  Some time ago I ran across some undertank
heaters for reptile tanks, would this work?  Is anyone using any
other system that they could share with the list?  I believe there
are quite a few people out there that would be interested.  Thanks.

E. Keith Johnson
Johnson City, TN