T5HO bulb...how often to change out?

[Aunt Caffy]

The vet told me I need to change out my bulb every four months to keep getting the UVB light. I have a T5HO bulb and am coming up on the four month mark. I have no problem spending the money, but I want to make sure I'm not trashing bulbs when they're still good.

 

[tortadise]

The HO bulbs have been known to produce UV up to and even longer than a year, the only exact way to know when to change them is to test the output of the Uv with a UV meter. If you don't want to spend the money on one.mid say 6-8 months but keep the old bulbs in case you do get a. UV meter and can see if the older ones are still producing good UV output. They cost a couple hundred bucks. But in the long run it is worth it. Can save lots of money by testing the lights instead of just swapping g them out, the older normal T5 bulbs last about 6 months. So this is where I can understand the vets statement. But no use in wasting money if you don't have to swap them out. Especially if they're still producing UV.

 

[wellington]

Usually at six months.

 

[wellington]

Didn't know about the to 8 months. Def not only four. That has never been the case that I know of. In the aquarium industries we recommend 6 months.

 

[mikeh]

Arcadia guarantees their T5HO tubes to produce stable UVB levels for a full year. I am not sure about Zoomed, but should be close. UVB meter is a sure way to confirm weather or not the tube is still good.

 

[Tom]

If you are relying on indoor UV as your sole source, you NEED a UV meter. I suggest this one: https://www.solarmeter.com/model65.html

I have never tested the HO bulbs long term, but I have a 4 year old MVB that is still producing a UV index of 7.1 at 14" through a screen top. I have no idea that is was still producing any UV. I was just using it for heat and light in an animal that didn't need indoor UV. 7.1 is the equivalent of full mid day summer sun. That is VERY high. In contrast, my brand new 10.0 regular (not HO) bulbs only produce about 1.6 to 1.7 at 11" with no screen.

The HO bulbs produce MUCH more UV and it makes sense that their output would last longer than the standard bulbs. A good meter is the only sure way to know. A meter will also make sure your bulbs are mounted at the correct height.

 

[Yellow Turtle01]

I change mine out at 6 months... but sometimes I forget and pass it out at 9 months... A good way to know when you bought the bulb is to wright in sharpie on the ceramic part of the bulb, so you know the exact date

 

[Tom]

I change mine out at 6 months... but sometimes I forget and pass it out at 9 months... A good way to know when you bought the bulb is to wright in sharpie on the ceramic part of the bulb, so you know the exact date

If you are going to guess and not use a light meter, then the best strategy is to buy a new UV bulb every fall, so your tortoises have a fresh one for fall and winter when they will be inside all the time. 6 months later will be spring time and your tortoise can get outside for real sunshine, so you won't need a fresh UV bulb. You can continue using the old one for light all summer long since your UV needs are be met by the sun.

 

[Yellow Turtle01]

That's a really good plan! Now that he'll be going out, I won't need to have it on in the summer/spring areas very much...