UV protection glass

[eugeneK]

Hello,

I have been in the hobby about 1.5 years

I have a Coralife HQI HoT fixture that was due for new bulb

I replaced the bulb with Ushio 150w 14000k DE bulb (old one was 150w 20000k Coralife bulb so its perfectly correct bulb)

The old bulb had a glass sleave around it (kind of like a hot-dog bun) and i assumed it was for UV protection

I put the fixture back together the way I took it appart to the T

4 hours later everything in the tanke was bleached and dead, fish acting funny, clam closed , shrooms hanging and meting...


I am assuming that UV glass wasnt Uv glass....


Can someone suggest a place I can buy UV protective glass suitable for MH fixtures please? or at least give me the name of it so when i call glass shoppes they dont look at me like I am retarded lol, I called like 6 and they were like hmm OK!


Thanks every one in advance.

-Eugene

 

[NewSchool04]

did you put the glass sleave back over the bulb? I use the same light and have a 14K Phoenix bulb in the fixture. I make sure the glass sleave is covering the bulb to stop the UV and haven't had any problems.

 

[pvtschultz]

You also stepped up from an old 20,000K lamp to a new 14,000K lamp so there was probably a considerable increase in PAR emitted. Regular glass will stop almost all UV radiation withing a few hundred nano-meters, that is why they use quartz glass on UV sterilizers. I am guessing that the increase in PAR contributed to the coral shock more than any UV.

 

[eugeneK]

yea I put it back on but its U shaped piece of glass, there is no way in hell it cover the entire bulb from front to back, I doublechecked the position af the glass sleave afterwords and it definately cover as much of the bulb as it can for its size...

I'll look at it again when I get home tonight, are you sure that that tube has UV on it and the bulb isn't sprayed with aanything? cause usually UV products require a stamp on them and mine didn't...

Another possibility and i will hate myself forever if this is what caused it.. when I installed the bulb the oter glass sleave had some salt stains on it from spashing so I wiped it with alcohol soaked tissue.... If glass was UV coated, could it be removed by alchohol?

...

 

[eugeneK]

PVT, in 4 hours tho at the same Wattage? I did consider that but seems like too short of a time to shock cause of intensity change.
I am not talking about shocked too, more like only skeletons left by this morning on anythinf top to middle of the tank and considerable damage to bottom corals as well as lion fish acting like its blind

 

[pvtschultz]

Glass filters out UV rays! That is why you don't get sunburn in your car and the reason tanning beds have quartz glass. There isn't a "special" coating for UV resistance. I think that double ended lamps are made of quartz to take the heat better since they are so compact which is the reason they are behind glass usually. Either you are getting UV being reflected over the bun shaped thing or the extra par is burning the corals.

 

[pvtschultz]

I understand where you are coming from. I went to Sanjay's page and doing a quick comparison of the 20,000K Coralife and an Aquaconnect 14,000K (he didn't have a Ushio 14,000K) you went from a PPFD of 30 to 37. That isn't a large jump, but they were new bulbs in comparison. If I assume that the old ones were a year old, you may have doubled the amount of PPFD going into the tank. Whether or not that is the case here, I really don't know.

Okay, I stand partially corrected:

From Wikipedia,

Ordinary glass is partially transparent to UVA but is opaque to shorter wavelengths while Silica or quartz glass, depending on quality, can be transparent even to vacuum UV wavelengths.

Tungsten-halogen lamps have bulbs made of quartz, not of ordinary glass. Tungsten-halogen lamps that are not filtered by an additional layer of ordinary glass are a common, useful, and possibly dangerous, source of UVB light.

This would include wave lengths of 315nm-380nm which is below what Sanjay's data goes to. So you may actually be seeing an increase in UV exposure, especially UVA which is not as dangerous as UVB and UVC which is filtered out by the glass. So I'm still not sure that the UV radiation is your troubles if you put the bun back of the lamp or there is some sort of glass between the lamp and your corals.

 

[eugeneK]

I'll see when I get home, I just know that I looked at some fixtures that are made by aquamedic and they have coating on it, its even a different collor, has a lot more blue to it. I googled UV protection glass and found some research that showes that glass filters some UV but not a all of the wavelenghs.

 

[eugeneK]

I was right...

I called Coralife, got transfered like 8 times, Got to speak to the guy in their engeneering department that works on their lights. He said that Coralife HQI bulbs do not produce UV under wavelenghs of 400nm (or something like that) and the rest gets filtered out by glass....

So i need a UV shield

 

[trmiv]

Every pendant manufacturer is using regular glass or tempered glass on their pendants, there is no need for special glass. I have an aqua medic fixture, it has a regular piece of glass. Go get a piece of float glass cut, and you're good to go.

 

[eugeneK]

Awsome!

 

[eugeneK]

so like Lows 2.5mm window glass is ok?

 

[trmiv]

That's a little on the thin side, I'd get something thicker so you're not concerned about breaking it all the time.

 

[eugeneK]

Gonna get the 2.5mm and stack 2 on top of each other, that would fit nicely into the slot where vent grill goes on the botom.

Thank you everyone for great responses, i am glad i posted here

- Eugene

 

[pvtschultz]

And be very careful about sharp edges. I had some thin stuff that I used to cover my FW tank and the darned stuff sliced me clean open without me knowing it until my hand was covered in blood. Just be careful!

 

[NewSchool04]

eugeneK, I read on some thread that Coralife does not recommend you putting glass in that slot, the light gets way too hot.

 

[mr pink floyd]

tempered glass wil lstop most UV, not jus tregular glass

 

[BeanAnimal]

Also stacking 2 pieces is a BAD idea. The loss will be considerable due to the 9 interfaces that light has to go through before it strikes the water. There is a SIGNIFICANT amount of refraction and scattering that will take place.

AIR
GLASS EDGE
GLASS
GLASS EDGE
AIR
GLASS EDGE
GLASS
GLASS EDGE
AIR

With a single piece of glass you only have 5.

AIR
GLASS EDGE
GLASS
GLASS EDGE
AIR

 

[eugeneK]

I see, thank you, i'll see if i can come up with a piece of tempered glass and if I use that slot i'll open one of the sides and install a high rpm fan to cool.

 

[BeanAnimal]

Does not even need to be high RPM.

Any local glass shop can get you a piece tempered for a few bucks (I am guess less than $10 for what you need).