I have a question about the day/night cycle for hermit crabs, I know there is alot of info out there about lighting, however I am thoroughly confused about night time. I figure that not every night would be lit by the moon/stars if they were out of captivity, so I only put it on once per week... But then their day/night cycle may be getting a bit muddled (they recieve indirect sunlight during the day, I do have a UVB light, but I need to find a way to keep up the humidity while its on so I currently don't use it) I have a small night glo incandesent light, that is very dim. Should this be used ONLY for viewing? If not, should it be left on all/every night?
My lighting turns on and off at dawn and dusk. I find they get around plenty during the day so don't need to wreck the day night cycle to view. I actually have two lights on slightly different timers so light come on and off in stages rather than bang its day or bang its night.
As for moonlight I don't do anything. Till we go to bed there is enough dim light from our room lights to simulate some then its just full darkness.
How big is your tank? I'm surprised the light affects the humidity. Is it in the tank or above it?
Annette
Carer of 5 Australian Land Hermit Crabs
Fili & Voldemort since 12/07/2011
Turbo since 29/09/2011
Frederickson & Kai 12/02/2012
and our new addition Stripey Ninja 25/10/2014
Thank-you appps for your feedback. I am sorry, but what did you mean by your second sentence "I find they get around plenty during the day, so don't need to wreck the day night cycle to view" That is a very good idea! normally, I will turn off my light when as soon as the lighting becomes a little lower, so they don't get a shock. I understand you do not have any night lighting, but do you think it would be beneficial/detrimental for them to have a constant glow?
My tank is a 40g. I have a approx. 40cm (18 inch) fluorescent UVB white light in it which sits on top of the screen cover above the tank. The rest of the screen is covered with a damp towel, but it is VERY hard to retain humidity in the tank for some reason (I have to soak the top layer of substrate once per week to stop it from becoming completely dried out!!!)
I guess what I'm saying is I concentrate on recreating daytime but dont worry about moonlight or trying to watch at night with a red light etc because they are active enough during the day for us to be happy to just let them sleep at night. I am only surmising but constant light isn't natural so I would avoid it.
I don't have problems with humidity in my big tank but had a little taste of your problems recently in an isolation tank. If it wasn't reading off the dial it was dropping too low. In desperation in the end I soaked a tea towel and sat that in there on top of a tank decoration and that finally worked. Mind you my crab had gone to ground so it was an ok solution. Not a good permanent one though.
I found it a lot harder to maintain humidity in the smaller tank. It was a real balancing act between adding water and opening lids to reduce it.
What I did notice though was the more surface area a water container had the higher it would send the humidity.
Annette
Carer of 5 Australian Land Hermit Crabs
Fili & Voldemort since 12/07/2011
Turbo since 29/09/2011
Frederickson & Kai 12/02/2012
and our new addition Stripey Ninja 25/10/2014
Lol. Maybe its us and not the tank size surely not lol
Annette
Carer of 5 Australian Land Hermit Crabs
Fili & Voldemort since 12/07/2011
Turbo since 29/09/2011
Frederickson & Kai 12/02/2012
and our new addition Stripey Ninja 25/10/2014
Years ago I used a light for couple of months, but it did wreck the humidity levels. (I have screen lids on our tanks, but have Plexiglas to help hold humidity in) We have skylights in the room the hermies are in as well as slicing glass doors. Through this they get plenty of light. Some use lights too to help with their heating. Here, we use UTH's and it works great.
Towels seem to help temporarily, but as they dry the humidity falls fairly quickly. If one has a metal screen lid, this will also cause the screen to rust eventually. Do you have cardboard you can cover with plastic wrap to help the humidity a little more?
Marie (aka ladybug15057)
If you are contacted privately (via pm or e-mail) and enticed to join another forum, please contact a Crab Crew member. This is an unethical practice.
I know this post is fairly old, but as an update, ladybug thank-you very much for the suggestion of cardboard and plastic wrap again! It has helped a lot with my summer humidity regulation (towels, bigger moss pit, soaked wood, more frequent mists etc.), as my family likes to put on the aircon on hot days, making it REALLY a hard to keep up the moisture. So I have plastic wrap taped down the side vent, and two covered pieces of cardboard on top, so I can overlap them to control the humidity VS airflow more effectively.
You're welcome! That was we did prior to buying the Plexiglas. Remember to try to leave a little opening at both ends for air flow to help kick back the possibility of mold.
Marie (aka ladybug15057)
If you are contacted privately (via pm or e-mail) and enticed to join another forum, please contact a Crab Crew member. This is an unethical practice.
I will stick to viewing and a occasional all nighter. 
