MH/HQI lighting for 72g bow

[Ninong]

You can also get a copy of Marine Fish & Reef USA 2002 Annual for $5.99 + $3.50 S/H = $9.49 total here: http://www.northcoastmarines.com/reef_annual.htm

That's where I got mine.

Ninong

[Claude Pool]

Richard:

Cincinnati Gasket Packing & Mfg, Cincinnati, OH, Phone: 513-761-3458 faxed me the specs on Robax glass. They would sell two pieces 101/2"x6" for $25.00 each. This is the size I would need for my minipendant. Probably same or close for you. If one of the luminaires' manufacturer were interested the price would be half in quantities of a hundred.

They talked me out of the Schott Borafloat because they feel being silicate glass it might shatter when hot if splashed with aquarium water.

The Schott Robax sounds great until you look at the optical data. It looks like there is a substantial amount of light transmission loss particularly in the blue wavelengths, less in the longer wavelengths. If I have some time in the next few days I'll try to figure out how to attach the chart.

Another potential problem is that Robax is a ceramic glass and direct contact with metal must be avoided. In my case the tracks are metal. It is recommended to use a permanently flexible, heat resistant material as an intermediate layer between the glass and metal. I don't know what that would be or how it could be adapted to the minipendants if at all.

Ninong:

thanks for the info

Claude

[Ninong]

Claude,

As a point of information: All of the AB-Aqualine fixtures use Schott Durax glass for the UV shields. This is just tempered glass. Which is one of the reasons that they specify 30 cm (12") as the minimum height for the fixture above the water. Believe me, I know, because I exchanged e-mails with them on this point since I have an AB-Aqualine Aquastarlight Future fixture. They gave me the following reasons for insisting that their fixtures should never be positioned lower than 30 cm above the water: Proper light spread, avoiding excessive heat transfer to the water, preventing possible damage to the fixture, and avoiding possible excessive UV radiation.

Evidentally they have decided that the Schott Durax product is the best for their particular application.

Ninong

P.S. -- The reason that I e-mailed the AB-Aqualine people in Germany about this question is because their operating instructions that came with the fixture were very specific in warning that you should never place the fixture closer than 30 cm above the water, and yet if you look at page B1.1 in their catalogue, you will see a picture of a Percula 90 tank with a 2*150w Aquastarlight fixture that is mounted no more than 7 or 8 inches above the water.

[bowfront]

Does anyone know what glass is used with the PFO mini pendants? Also what is the manufacturer's recomended height for these (distance from bottom of pendant to water line) same as AB? I'm a little confused at this point on the tempered glass issue. AB uses Schott Durax ok but Claude mentions Schott Borafloat and Robox. Are any of these one of the same or three different types of tempered glass? I thought PFO was advertising that the glass in their mini pendants has some type of UV protector. Is this just the ability of tempered glass to block some UV that they are hyping? Is there really an issue for personal safety if the lights are sheilded with tempered glass? Obviously corals don't seem to be bothered by either the PFO or AB setups or we would be hearing about it from users.

[Ninong]

The only thing I know is that I have read in more than one source that tempered glass is the recommended UV shield for HQI DE lamps because it is more heat resistant than other materials. I would hope that AB-Aqualine knows what they are doing when they use Schott Durax tempered glass in their fixtures.

Ninong

Ref: TRA-1, p. 196: "Because of the heat generated by HQI metal halide lamps, only tempered glass should be used for the lens..."

[Claude Pool]

Ninong

Yes I was aware that the AB fixtures use Schott Durax and that it is tempered glass which of course does not filter dangerous UV.

The glass I was referring to is Schott Robax which is a glass-ceramic. Quoting from the product info sheet : "As a result of its extremely low thermal expansion ROBAX(r) can be subjected to extreme temperature differences.... its diverse range of applications include chemical process sight glass, high temperature vision windows, heat insulators, commercial ovens/broilers, architectural and outdoor lighting, electronics and UV light wave blocking applications ....the temperature shock reistance (TSR) of glass-ceramic characterizes the ability of a panel to withstand a temperature shock in which cold water is poured onto a hot panel" Maximum operation temperature is 1400degree F for short term usage, 1258degree F for long term usage.

As I mentioned in an earlier post, I see the decrease in light transmission, particularly in the blue wavelengths, as a drawback. I would like to run the Optical data by Dana Riddle and get his opinion.

Charlie

As explained above, Schott Durax and Schott Robax are very different. So is the Schott Borafloat which is a borosilicate glass similar to Pyrex.

I spoke to PFO several weeks back regarding the glass in their mini-pendants. I was told it would absorb UV but I was not able to find out what kind of glass it was or any further information. I might try again now that I now a little more about what is available.

I also have a call in to Pyrex who do manufacture "Pyrex-UV-Plus" which sounds very similar to Schott's Borafloat. I am very interested in finding out if it would sustain water spashes and at the same time not reduce light transmission as drastically as the Schott Robax.

Claude