Quote Originally Posted by kitedemon View Post
Racks do not work well in anything less than 78ºF I know mine is in a room that is 70ºF from experience I can tell you it is a serious PAIN and very costly to get everything correct at this temp. I cannot recommend strongly enough to just heat the room up to 80 and simplify your life! I am in a very old place and it just is not cost effective to do this (2 x 1800 oil heaters to hold 78-82 in this room they rarely shut off. Very expensive)

If you like me can't I'd first recommend against the rack it is too inefficient to handle these temps. I'd look at custom enclosures like boaphile or visions. If that isn't an option 4 inch will not work and I'd suggest 11 you will need a secondary heat source and I'd look at the 17 lower wattage tape it does not get as hot. The rapid heating of the 11 inch I'd really suggest against on/off type t-stats and go with proportional ones, you will need one (at least) for hot and cool elements. I found that there was so much variation between top to bottom I have the 11 inch on two separate probes bottom half and top half (that is three if you are keeping track I use a herpstat pro) I have a insulated rack top bottom and sides with 1/2 inch blue or pink foam. The last thing is as the tub is sitting on 27 inches of heating you really really should use a failsafe t-stat (on/off type) because if a probe moves or the t-stat fails there is no escape from the heat for the snakes.
Ya 80 is not an option there. Its in the basement and if I have the little heater turned off it gets to about 65 I am working on insulating in the area to keep in the heat. I will say this I have a small rack that I made using 12qt tube and I know I am going to have to reconfigure them to belly heat they have back heat right now. They are keeping the hotspot at between 87 to 91 and I have two 3" strips thats 1 per row and it keeps the temp stable I am thinking that 11" on belly heat would be too much for a 28 to 32qt rack.