Hi,
I have the same set up. I have had it for several years. I have been told by the pros that the only thing you don't want to see is visible moisture from normal everyday living . When my snakes urinate the fronts of my tubs fog up. So, I have had no health problems ever and all my snakes give me perfect sheds. I also live in Denver where the average daily humidity is below 10 percent ambient. As long as you are not seeing a fogged up tub you should be fine.
Bill
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2.1 Tripple Het Caramel, Orange Ghost, Genetic Stripe
1.1 Het Lavenders
1.1 Het Caramel Albino
0.1 Het Albino
0.1 Spider Het Albino
0.1 Het Pied
1,1 Pastel Het for Orange Ghost
1.0 Albino
0.1 Spinner
1.1 Super Pastel
0.1 Jungle Pastel
1.0 Pied 50 percent White
0.1 Clown
0.3 Normal
1.1 Kids
0.1 Spouse
1.0 Chocolate Lab