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Cultivated Reef

How important is UV shield when using MH?


RLiu818

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I just spoke to the guy who is making me a custom hood from petsupplyliquidator. He is making me a 70W MH + 1x36W PC combo. It is the solar model so he says it doesnt have a splash shield or plexi shield. Therefore there is no UV filter for the MH.

 

 

Is this bad? Should I try and install a glass shield myself?

 

 

 

This is for my 10 gallon tank. I am still undecided on what corals i will keep.

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PAR, UV Burn and Bleaching = BAD.

Use some glass.

Glas tops will also prevent airborne particles from setling on your tank water and help eleminate high evaporation rates there by making a more stable environment.

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if it can survive the temp you can try acrylic sheet (a natural uv filter). their survivability will definitely depend on the distance from the mh tho otherwise you'll have plastic stalagmites in your tank. X)

 

you have to have something to prevent splash hitting the bulb which could result in the bulb bursting/cracking (temp shock).

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Most MH bulbs have an outer glass envelope (separate from the glass reaction chamber) which cuts out almost all of the damaging UV. The ones you need to be very careful of are HQI bulbs with no outer glass envelope, they really need to be run with UV filtering glass.

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don't get the folding glass canopy. THey suck ass. they will rott and crack with the salt and the intense heat and will yellow with the U/V radiation. Best bet, go to a glass shop and have the, cut a SOLID 3/16ths. piece of glass and have then round off the edges lest you cut yourself with a nasty glass slice.

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quiksilver5768

the UV shield glass always comes with any HQI hood at PSL.com...why dont you want one? They help take away the UV rays and they REALLY help in keeping the heat constant in the tank (HQI bulbs run REALLY hot and a splash of water could cause the bulb to burst unlike with mogul bulbs which are more tolerant). The heat from the bulb ends up being trapped in the hood rather than dispersing over your tank and causing temp swings when the light turns on and off. In order to remove the heat trapped in the hood, thats what the fans are for....I would highly recommend geting the glass shield with the hood. I even recommend getting a glass shield even with a mogul socket MH just to avoid heat problems.

 

 

EDIT - i thought you were saying that you didnt want a glass shield on there but it did come with one.....just email PSL and im sure they could work out a hood with a glass shield for yoy. They are very good at replying about custom hoods...

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this is a little off topic but ive gotten a sunburn through a car window before. if glass filters out uv rays then why did i get a sunburn? im not challenging the fact that glass filters uvs im just curious.

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the uv protection depends on the additives or coatings (depending on the process and end-market). glass isn't inherently uv resistant like acrylic is but it can withstand much greater temps. polycarbonate also isn't uv stable (unless you add additives) but they can take the high temps generated by mh's.

 

that's why you see polycarbonate lens used in those parking lot lamps and streetlights. problem is that the uv lasts no more than a couple of years (if that) from exposure from the mh and the sun. then you gotta replace those streetlight covers (hehehe, then you gotta buy another one from me :P )

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Quoted from Coral dynamics website.

Corals that live in shallow-water are typically exposed to high levels of potentially damaging solar radiation. In addition to this potential damage from the sun, the coral's situation is made even more difficult by the release of oxygen that is produced by the algal symbionts during photosynthesis.

 

Even with these potentially damaging scenarios, coral animals are able to withstand long-term exposure to damaging amounts of ultraviolet radiation from the sun. Scientists believe corals posses a compound that acts as a type of sunscreen for these organisms. These compounds, known as mycosporine-like amino acids (MMAs), have the ability to efficiently absorb UV light. Corals are either able to accumulate enough MMAs, either through producing them or accumulating them through feeding, to protect themselves against the strong solar radiation that is typical of tropical areas. Researchers are even investigating the possibility that these MMAs may be able to be produced to provide another type of sunscreen for humans.

 

HTH

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Originally posted by Dave ESPI

don't get the folding glass canopy. THey suck ass. they will rott and crack with the salt and the intense heat and will yellow with the U/V radiation. Best bet, go to a glass shop and have the, cut a SOLID 3/16ths. piece of glass and have then round off the edges lest you cut yourself with a nasty glass slice.

 

http://www.all-glass.com/products/hoods/default.html

 

 

AGA also offers the 3/16 which is commercial quality i suppose. What do you think of this? I think it will be a hassle getting it through a glass cutter.

 

 

What if i go to homedepot and get a custom cut acrylic cover? Will the acrylic be ok with the heat? will it protect from UV?

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quiksilver5768

You must be avoiding my replies....look, read again...

 

"Im saying that you can ask the guy to add on a shield for you....its not very hard for them to do. They take special requests all the time..."

 

At the most, they will charge you about $5-6 more.....

 

Why not take my advice.....And also, the acrylic will most likely get too hot and melt....you would need some pretty thick acrylic in order for it not to bend or melt....

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There are new Iwasaki 150 watt HQI "aqua" bulbs that run a gorgeous spectrum with no supplementation.

 

You can get a completely contained bulb, ballast, and all right in the pendant WITH a glass shield.

 

I think it is the perfect NanoLite for light-hungry corals and clams.

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