Moderating humidity/increasing ventilation with fans - a good idea?


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Jul 9, 2020
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I'm very aware that the new vivarium that I made a few days ago will have issues with ventilation; it sits in a corner of my room with little ventilation and at this point in time the LED lamp sits atop the enclosure, blocking most of the mesh and therefore the ventilation. This will be changing though as I will be moving it soon to a new, airy spot where the lamp can be hung from above to allow air currents to move in and out of the mesh. To that end, I was wondering if it was worth getting a small fan (something like this (yes, when I said small I meant small)) which could be attached to the exterior of the enclosure to help air move around - I imagine this would be quite necessary for species like the Orchid and Giant Asian, for whom ventilation is key and humidities are important (I find that at the moment the humidity is ~70%). Is this likely to stress a mantis out? It wouldn't be on the whole day, just a couple of times a day to refresh the air inside.

It's not a bad idea. I've been thinking of getting something similar for my vivarium. 

- MantisGirl13 
I got mine today and I can recommend this make, if you can get it in the USA - I got the Eluteng 80mm fan, on Low it is really quiet and doesn't make too much of a disturbance as to stress out a mantis but will certainly keep air circulating in the viv. I'm now wondering whether to keep it on a timer or not; during the day makes the most sense as the buzzing is less likely to annoy me but during the night the viv humidity skyrockets, I'm assuming because transpiration becomes the primary plant activity as opposed to photosynthesis. Perhaps I'll have it come on at regular periods - over 15 minutes of activity it should be way more than enough to completely recycle all the air in the vivarium according to the stats. I'll keep my findings/thoughts on here!

Edit: added calculations, they're patently wrong and they don't account for the fact they're blowing through micro gaps in the viv but ah well, I like maths.

The fan on low is rated to 25 cubic feet per minute (cfm); in non-freedom units, that's 0.707921 cubic metres per minute. My vivarium is 20cm * 20cm * 30cm, which gives a total volume of 0.012 m3. Dividing viv volume by fan capacity gives how long to fully recycle all the air; in this case, that's 0.01695 minutes, or just over 1 second. Accounting for the assumptions, I'd say a 15-minute spritz every few hours is more than enough to stop things getting stagnant without losing too much humidity, but I have a chart of viv humidity over time so I can track the effect.


View attachment plot.html

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