[bbrock]

Brent,
since youve used a true spectrometer, and were able to see the levels for each nm, maybe you can explain the lesser priced solarmeter which just provideds an index. i feel a TON of information is lost between the two units and may provide a false ok for other hobbiest. Being you have seen what bulbs produce what in your viv and at the different heights, that you are able to only now need to do monthly or so checks for intensities to monitor bulb replacements, but what do you think is the best option for people that are just setting up UV in the vivs?

This is something I'm still trying to figure out. First, let me clarify what I have used. I used a spectrometer to measure the transmissivity of Solacryl and also a piece of acrylic I picked up at the local HD (and verified that it blocks almost all UVA and UVB). This was a large bench unit without a portable probe. For measuring light levels in vivs, I have used a LiCor septometer set to record photosynthetically active radiation (PAR) at the tip. That measured how much light that could be used by plants was striking a particular spot in a viv but didn't break down that light by wavelength other than limiting measurements to within PAR. So I haven't ever had my hands on a device that could measure UV in a viv.

Bear in mind that I'm still researching the latest UV meters myself so am not an expert. Solartech offers a variety of units that measure and report different things: Welcome to Solartech. The UV meter group uses mainly the 6.2 which measures UVB and reports the measurement in microwatts/square cm. The 6.4 reports D3 IU/minute. To me, using the 6.2 makes sense since you are recording the UVB energy measured by the unit rather than some calculated index which requires assumptions about whether that index translates to reptile/amphibian use. But sensors in meters vary in their sensitivity response curves so not only do the meters differ in the band width they measure, but also to peaks within that bandwidth. So two lamps that produce the same level of usable UVB might test different if one bulb produces a peak at the meter's band of maximum sensitivity while the other produces a peak off that max sensitivity. But at least we are getting some quantifiable measurement.

What I have done up to this point is use the size of my viv and the manufacturer's stated distance from bulb of producing a therapeutic dose as guidance. Of course you have to trust the manufacturer but I choose a bulb that will throw a therapeutic dose at least 2/3 of the distance from top to floor of viv but ideally to reach just to the floor and not much further. I count on vegetation to block and filter the UVB to create a patchy mosaic of UVB within the viv. I have my UVB bulbs on the same timer as other bulbs so they are on all day. There's a lot of guesswork in that approach but it seems to work. But with a meter in hand, I would definitely combine measurements with the dosing info that Ed has been digging up to adjust intensity and duration with a little more confidence.

 

[parkanz2]

Are most bulb manufactures compliant when it comes to providing emission data? If you can get that data for a new bulb a meter still seems valuable even if you can't measure the energy of all wavelengths as with a photospectrometer. You could at the very least monitor the decay of the bulb as well as the penetration into the viv. This is assuming you can trust the manufacturer which is a different issue I suppose.

I still need to read more about the different meter models but I've been leaning towards the solarmeter 6.2 as well but as far as monitoring lamp degradation I wonder about the 5.7 model for a UVA + UVB reading as it's been shown that UVA is also involved in vit D3 physiology.

 

[motydesign]

i agree with everyone, however the 6.2 i feel isnt as useful unless you have a understanding of what your light is producing and create a bench mark to work from. let me see if i can describe my theory of how i think this needs to be done if it were going to be done correctly.

a spectrometer capable of 290-400nm is required at time of bulb install (you will need to use the same bulb every time you replace for bench marking to work... this also assumes that manufacturing will stay with in specifications) you will then also need your 6.2 meter.

once all materials are procured you can install and turn on the bulb (allow warm up of mercury vapor) and then take measurements with the spectrometer finding what wavelengths your light is producing and at what intensities, then record it. this is for the hobbiest understanding of what they are dosing (each set up will be slightly different depending on how the viv was set up( solacryl, saran, open hole...). this is needed as the 6.2 only measures the 295~nm length which leaves out all info of UVA or any other gradient. so now that you know what you are really dosing the 6.2 can be used to start your bench mark. this 6.2 measurement now needs to be recorded. 6 months later the spectrometer needs to check what you are producing once again and record it then measure with the 6.2 the more you can do this in between the more accurate your bench marking will be. i may have an incorrect thought process here but my hypothesis is different nms will decay at different rates and this will NOT be recorded in the 6.2 since it is measuring such a narrow band.

at this time you no longer need the spectrometer


PLEASE feel free to correct me if there is error in my theory . this is my idea on the correct application and do not assume that is 100% correct.

 

[parkanz2]

It makes perfect sense Motydesign. The only problem is that very few hobbiests, if any, aren't going to want to buy a 5.7, 6.2 and a spectrometer. Can we settle for one piece of equipment and infer other information from that data based on manufacturer specifications?

 

[motydesign]

first of all i never said all three devices were needed... just the two expensive ones

unfortunately no... i have never seen data on decay of the spectrum just initial output (and i have always questioned how much of that was real until that article Ed posted of side by side testing)(but even this did not test what i am suggesting)

the 5.7 i feel isnt as useful to us as the 6.2 would be after a bench mark was created.

some one needs to bite the bullet or at least have a unit available to borrow for a bit.

this is what we need for each light we want to use (this is an example not an actual reading of UV light)

 

[ckays]

I wonder how much of this testing has already been performed.

Have you look into the UVB Meter Group @

UVB_Meter_Owners

It's yahoo group that I have been subscribed to for years now. I stopped going through the data a very long time ago (my needs were met) I will go back through all of the "newsletters" over the next few days to see if I find anything pertinent.

I would bet that much of this testing has already been performed I'll start digging.

 

[parkanz2]

That would be great Ckays. Hopefully uvguide.co.uk gets their data back up soon as well, it seems like he does a very thorough job.