Question for T5 Users

[fijiblue]

Kyle-

I am waiting till the tank is one year old to post full frontals and setup - April 15th.

[lewismw]

How do you obtain PAR ratings for your tank?

[siwelk]

Originally posted by fijiblue
Kyle-

I am waiting till the tank is one year old to post full frontals and setup - April 15th.

April 15th?!? youre killin me smalls...


thats one helluva birthday, better have your taxes in


thats cool i guess, i was just kind of trying to gather information about similar setups now since im currently in the building stages.
if you find it in your heart maybe you can PM me some details about your equipment at least, that way i can make more educated decisions on what im going to be buying between now and then. i eventually want to keep SPS and anything you can give me would help out. thanks.


-kyle

[hahnmeister]

Originally posted by PaulErik
T5 HO lamps built to current commercial standards/specifications have a Cold Spot/Cold Foot located at the labeled end of the tube. Not all T5 HO lamps in the aquarium industry have them.

You can usually see if a T5 lamp has a cold spot. The lamp when lit will have a dark area where little to no light is generated by the labeled end.

You can see the explanation and a picture of the cold spot in a T5 lamp without the phosphor coating in this thread: http://archive.reefcentral.com/forum...readid=1159820

Originally posted by PaulErik
GE, Osram, Philips and Narva manufactured T5 HO lamps are built to the same type of standard. They will not light up at the labeled/stamped end of the bulb for a good reason. This is called the cold spot in the lighting industry.



In a fluorescent lamp the light output is determined by the mercury vapor pressure which is determined by the temperature of the liquid mercury. Liquid mercury is deposited on the inner wall of the bulb at the coolest spot. In a stabilized T5HO lamp equipped with a cold spot the liquid mercury will be at the labeled/stamped end of the tube.

With these lamps the cold spot is usually cooled to maintain stable light output and doesn’t require cooling of the whole tube. This technology keeps the lamp very stable because the liquid mercury is located in one spot.

When testing a T5 HO lamp with a cold spot the lamp generally requires a few on/off (heating and cooling) cycles so all of the liquid mercury goes to the cold spot. The lamp should be seasoned for approximately 100 hours. Generally in the lighting industry the recommendation is to re burn (burn in) the lamp for additional 4 hours minimum if the lamp has been switched off for 12 hours or more. A re burn (burn in) is also needed if the lamp is moved or oriented differently. A T5 HO lamp is considered stable if changes in light output are less than 0.5% over a 5 minute period after the burn in period.

Metal halide and fluorescent lamps can be very sensitive and should be tested carefully or the readings will be useless. This is why the lighting industry has standards and specifications on lamp testing.

So then how do you cool a lamp w/o a cold spot? Does this mean there is a different method that we can use? On lamps with cold spots, are waterproof endcaps a bad idea then because they can overheat the bulb at the cold spot with all the rubber insulation?

[hahnmeister]

Originally posted by The Grim Reefer
Dunno, The Giesemanns use them and I have heard from a few people that really don't like the lamps, didn't last long. Not really sure if there is a real advantage one way or another/ A lot of things can kill a lamp

That must have been why my G-mans lasted me forever.... I had that cross-flow fan blowing right onto their cold spots. Those bulbs were still going strong at 18 months!

[PaulErik]

The whole tube should be cooled if a lamp does not have a cold spot. The mercury will be distributed through out the tube or where ever the coolest spot is. The only way to keep the lamp stable and operating at optimal output is to keep the whole tube at a proper temperature.

I really don't know the affect of using waterproof end caps on a lamp with a cold spot. The general recommendation from lamp manufacturers is to keep the cold spot at the coolest end of the fixture. If a multiple lamp fixture draws air from one end of the fixture the labeled end of the lamps should all be at this end. Another thing is you do not want to over cool the ends of the lamps. The cathode must operate within a certain temperature. If the cathode is too cool this will cause excessive sputtering and the cathode will fail prematurely. This can be a problem when dimming T5HO lamps. When dimming is used cooling should me minimal and the ballast must provide additional cathode heating.

[HecticDialectic]

Originally posted by fijiblue
Does anyone have PAR ratings for their tanks? Here is mine.

So that's the same picture you posted on the thread where you said you had 2 blue+, 2 ab special, and 2 procolor, except with PAR numbers added. ( http://archive.reefcentral.com/forum...9#post10898829 )

Are those the PAR ratings for the old combo or the new combo? Could you post front-shot pictures of the new bulb combo you're running so that we can compare how it looks to the setup with procolor bulbs? I'm sure you didn't mean to, but it's a bit misleading to tell people your new bulb combo while showing a picture of an old bulb combo. I'm just curious, because I loved the color of the old bulb combo, and would like see how the new bulb combo compares.

[fijiblue]

HecticDialectic -
Sorry for the confusion. That is an older pic of my tank...I just didn't want to post a newer pic with the readings. The color is still similar - instead of a pro color, there is a uv (same color) and one more B+ instead of another pro color. I didn't like how weak the pro colors were.

[jennmac415]

Figi... so what IS your bulb combination now.. I am getting confused too...and can't you please post a couple of new pics with a PART of your tank so I can see what your new combination looks like.. I am thinking that is maybe what I want to go with and I would really like to see it.

Thanks!

[jennmac415]

Figi... so what IS your bulb combination now.. I am getting confused too...and can't you please post a couple of new pics with a PART of your tank so I can see what your new combination looks like.. I am thinking that is maybe what I want to go with and I would really like to see it.

Thanks!

[Bud's Reef]

My 120G with T5 retros is still a work in progress and I haven't decided the right height yet for the bulbs so this thread is of real interest to me. Is salt spray a problem for the reflectors for you guys that have the bulbs just inches from the top?