I purchased a C-Serpents combo rack about 6-8 months ago to mainly use as a quarantine rack when I get multiple animals of different sizes in. Up until this point I have only used the v35-s tubs and below. I am going to a show next week and had planned on purchasing a few animals 3 months to 2 years off the same guy who I have bought from in the past. Well. I get the tubs set up and realize there is a big problem. The smaller tubs heat 10-12 degrees more than the larger ones.. At first I thought it was just a glitch in the thermometer or the heat gun but after having it set up for 48 hours with just substrate and water in the bowls the bigger tubs run a nice 88-91 on the heat tape side and the v35-s and smaller all run 100+.. Might be a long shot that someone else has dealt with this but I will give it a shot.. I should have realized this before purchasing given basic science..
The only way I can see correcting this is running separate heat tape to each level with two stats or one with two zones.. Or venting the top tubs which would require the rack to be taken apart..