Tank Top Lighting**red light & UVB info

Guest · Post by **Guest** » Mon Aug 15, 2005 11:22 pm

I've been doing a lot of reading about lighting for Hermit crabs on here and on other sites. It seems most people feel comfortable with the moon glow bulbs and more people are starting to use full spectrum/UV bulbs during the day time hours. The Repi-sun 2.0 gets mentioned often.

I'm planning on trying this, but I have a 24" fixture and the bulb for that is 18-watt while many people recommend not going over 15-watt. With a bigger tank (I have a 20H) is a little more wattage okay? The tank is fairly deep so I figure the crabs can move closer or farther from the light as needed. I was planning on running the daylight bulb during day time hours and then have the moon glow bulbs at night.

Should I go 12 hours with each? Or 14 hours with moon, 10 hours with daylight?

Edit title only-CM

Guest · Post by **Guest** » Tue Aug 16, 2005 6:56 am

I'm not sure about the distance, my advice would be to give them a shelter, (cave or something) while you keep a close eye on the temp. Make sure you temp several levels of your crabitat several times during the day. I'd pic a day when you can be home all day.

I've heard others say that for light 12/12 is best because so many crabs live near the equator.

Guest · Post by **Guest** » Tue Aug 16, 2005 8:45 am

They have plenty of shelter. I have a couple coconut huts, fake plant leaves, deep forest bedding they can dig into, etc. Right now my under tank heaters seem to having a hard time keeping the tank at 75F so I'm hoping the light might get me up in the 76F range.

Guest · Post by **Guest** » Tue Aug 16, 2005 8:59 am

3 extra watts of fluorescent light won't hurt anything. They do emit heat, but not that much heat.

I use day incandescents on my 120 gallon tank, or my temp would always be too cold. In the winter, I've used up to 150 watts of incandescent and 30 watts of fluorescent all at the same time!

As long as your tank conditions are stable and in range, it doesn't matter how you get them there.

Guest · Post by **Guest** » Tue Aug 16, 2005 5:36 pm

Do Hermit crabs see red light? The moon glow bulbs don't provide much visible light and I noticed if I shine in a red light from a LED flash light it doesn't seem to disturb them. So would a red light, that doesn't put out much heat, bother them if left on all night? I was thinking a moon glow in one socket and a red light in the other since my light strip has dual sockets. Right now I have two 15-watt moon glow bulbs.

Guest · Post by **Guest** » Tue Aug 16, 2005 6:46 pm

No, I would avoid red spectrum lights at night. It's not natural for them.

Guest · Post by **Guest** » Tue Aug 16, 2005 8:09 pm

Julia_Crab wrote:No, I would avoid red spectrum lights at night. It's not natural for them.

Point taken, but aren't red lights not natural for all reptiles and snakes, but many people use them since they are designed to not bother them?

Guest · Post by **Guest** » Wed Aug 17, 2005 2:41 am

WadeF wrote:They have plenty of shelter. I have a couple coconut huts, fake plant leaves, deep forest bedding they can dig into, etc. Right now my under tank heaters seem to having a hard time keeping the tank at 75F so I'm hoping the light might get me up in the 76F range.

I love the conut shell huts there so cut i just got one and all my crabs love it

Guest · Post by **Guest** » Wed Aug 17, 2005 4:00 am

I use the moon glo bulbs, and for awhile I used a dim blue light in one of the sockets. Once it burned out I couldn't find another one like it lol ... all of the other kinds I tried were brighter, and I didn't feel it was natural to have it bright like that at nighttime. So now I just use the moon glo bulbs (they get plenty of natural sunlight during the daytime), but the dim blue bulb didn't seem to bother them during the time I had it.

Guest · Post by **Guest** » Wed Aug 17, 2005 8:42 am

WadeF wrote: Point taken, but aren't red lights not natural for all reptiles and snakes, but many people use them since they are designed to not bother them?

Red spectrum light is daylight. Use it in the daytime, not at night, that's what I was trying to say.

Guest · Post by **Guest** » Wed Aug 17, 2005 12:14 pm

Thanks for everyones' input. It seems like everyone is still experimenting with tank top lighting to find out what works best. I noticed some people have just started with the Repi-sun 2.0 bulbs and have been happy with the result. I just installed mine to replace the standard purple flour. bulb the light strip came with. Guess what? Crabs starting coming out from everywhere and started moving around, basking, etc! The repi-sun 2.0 appears to be the lowest emitting UVA/UVB bulb in their line. So hopefully this will prevent the crabs from "frying", where Repi-sun 5.0 and 8.0 have increasing amounts of UVA/UVB output that maybe to much for the crabs, or result in them basking for shorter times and spending more time hiding. Just my thoughts.

If the crabs bask for short amounts of time in their natural habitat you would think a low level UVA/UVB would result in them basking and being active for longer periods of time during the day.

For night time I'm running two 15 watt moon glow bulbs by ESU Reptile. They call them "NightLight" and are the only ones I found that state they are coated with "RARE EARTH BLACK PHOSPHORS to simulate the natural glow of the moon".

I also picked up EXOTERRA's NightGlo Moonlight Lamp bulbs, but they don't say anything about using the rare earth black phosphors and seem to just rely on the dark blue glass to do the job. So I'm sticking with the ESU bulbs.

Today I switched out 1 of the 15 watt's for a 25 watt. So I have a 15 watt and a 25 watt. I'm monitoring the temperature under the bulb to make sure it doesn't get to hot. With the two 15's and my UTH's the temp was around 74F so I'm hoping to bring it up to the 75-76F range.

I do have a question. Is it okay to leave the moon glow bulbs on 24/7? I have the daylight Repi-sun 2.0 light on a timer to be on from 8am-8pm. I could put the moon glow bulbs on a timer to have them be on from 8pm-8am, but if it doesn't hurt to leave them on 24 hours a day it would help keep my tank warm.

LOL! As I was typing this my meat probe thermometer's alarm went off. The upper part of the tank, under the 25-watt moon glow bulb, hit 80F. So I guess I'll go back to the 15-watt.

This leads me to another question, should all parts of the tank be kept under 78F? If say the top of the tank, where the crabs could reach if they climbed all the way up their choya wood, is 80+F, but the middle and bottom of the tanks is in the 75-76F range, is that okay? I figure the crabs could move away if it's to hot, but I don't know if short exposures to heat over 78F is bad?

I noticed when I put in the 25-watt moon glow one of my E's climbed up the choya wood right under it and got as close as it could, but then retreated after awhile.