What incubator can keep 21-23 degrees C, and hold open containers of water, without dying?

[Michael Levin]

I am keeping a largish colony of flatworms (planaria). They live in open
tupperware containers and need to be between 21 to 23 degrees Celcius. The
temp of our lab varies (the AC system is shut off at night), so I got an
incubator. The thing died after a year and a half, and I was told it's
because 1) the target temperature is close to the ambient room temp lots of
the time so that the machine has to keep cooling/heating back and forth
continuously, and worse yet, 2) the open containers of water evaporate and
lead to condensation. So, I'm looking for advice: is there a (hopefully
under $5,000) incubator/chamber of some sort which can keep to about
room-temp., in a room which is sometimes that temperature and sometimes not,
and handle the fact that there will be lots of open water containers in
there? Surely someone has had a need for something like this. If anyone has
any thoughts, please cc: your post to mlev...@comcast.net (my ability to
read newsgroups at work is very limited). Thanks in advance!!

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Mike Levin
mlev...@comcast.net