HELP!!!Tek Light Loosing Output!

[fijiblue]

Ok, so after reading the long T5 thread (thanks Grim) I decided to purchase a Tek light for my SPS tank. I got the 36" 6 bulb fixture. I installed 2 blue plus, 3 aqua blue specials and 1 aquasun for more red color. Everything looked great and the output on my water's surface was 43,000 lux. Since I took that measurment, I have lowered the lights to about 4" from the water's surface. The other day I decide to test it and it is now at 31,000 lux! Do these ballasts get weaker with time? I thought it might need a fan to run cooler and better the output, but I put one on and it is still reading the same.

 

[RichConley]

How long ago are we talking here?

THe bulbs lose, IIRC, about 10-15% in the first month or so, and then level off. (halides do this too)

 

[old salty]

If you are using the acrylic shield on the fixture, I highly recommend you remove it. Both of mine have warped from the heat that is contained. This heat can make short work of the bulbs.

 

[fijiblue]

RichConley - It has only been about a month.
old salty - I do use an acrylic cover. I don't want to go with out one because of the salt splash. Do you think I can run a fan through that part to cool them down?

 

[fijiblue]

Anyone else heard of this?

 

[8BALL_99]

All bulbs loose output in the first month or so... Nothing is wrong with your fixture..

FWIW I had 2 36"x6 bulb fixtures over my 125 for a year.. I sold them and got coralife 3x150watt mh fixture.. My tank looks a ton better.. Much brighter and alot cheaper when it comes time to change the bulbs.. I dont' think T5s are all that great.. Better then PC's maybe but nothing compared to MH.. Just my rant anyway..

 

[fijiblue]

8BALL_99 - I appreciate your opinion. I was a MH user and figured I'd try T5's. At first, I was impressed by the output, but now....not so much the case. I agree with you that halides make the corals look much nicer. I am not going to give up on them yet, though. I am hoping to find a way around this. I am thinking I might have to overdrive the 4 daylight bulbs with an icecap and see how that goes. What do you guys/girls think?

 

[old salty]

If you wish to keep the acrylic shield on the unit, you have to expect a lower output from the bulbs; they are getting very hot. Overdriving the bulbs will only increase this effect and really shorten the bulb life. Since everything is give and take, I removed the acrylic shield, raised the fixture up another 2 inches, and added a few computer fans. The salt spray is quite minimal, and the cooling effect more than made up for the fixture being 2 inches higher off the water line.

 

[fijiblue]

OS - What type of bulbs do you use? Have you measured your lux at the water's surface? If I can get it back to 45k at the surface by removing the cover and using a fan I will for sure consider it!

 

[DarG]

I might be dense but how are you going to get the new bulb output back to where it was when it's a given that the bulbs, all bulbs, lose a certian percentage over time?

 

[fijiblue]

T5's will run roughly 20% more output when the ballast and bulbs are kept cool.

 

[old salty]

I was using Giessmann bulbs. I brought home a light meter from work, but alas it only works with "Billy" lights (for jaundice patients.) I can only tell you from my experience with trying to get the most from my lights. The heat trapped by the addition of the acrylic shield not only warped the acrylic shield, but really put a hurtin' on the bulbs. My latest set of bulbs are 6 months old and almost as bright as the day I put them in. At $300 to replace all 12 of my bulbs, I assure you that early bulb replacement is something I took great steps to avoid. If this means having to wipe down the lamps once every two weeks or so, that is the small price I was willing to accept.

 

[jamesdawson]

Teklights are total crap. They look sleek, but because of no active cooling they only put out 1/2 the PAR of a quality fixture with active cooling. Their reflectors stain and permanently discolor from the inevitable salt spray and if you put a shield on them the already overheated bulbs just cook and lose further output.

You would be smart to get a SunPower or for the ultimate cool looks--a PowerModul, they will blow away both the Tek in PAR and efficiency. They can be hung or set on top of a tank. ReefGeek has them coming in a month or two. Better call and reserve one (no charge for this) in order to ensure getting one on the first shipment. Coolest thing about ATI fixtures is they only have one wire from the fixture to a remote mountable box where it splits into multiple wires for the bulbs. Very clean setup IMHO!

James

 

[hahnmeister]

You can keep the tek sheild on, notch out one end and bend it down with a heat gun or acrylic bender (or, just cut it off if it comes to it). So it looks like this in 3D...

Then attach a computer cross-flow fan to the side so it blows across the bottom of the fixture. Here's the fan...

Here's an adapter to run the fan at about 6v...

Clip it to the side of the fixture like so...
<a href="http://photobucket.com" target="_blank"><img src="http://i90.photobucket.com/albums/k278/wetworx101/CrossFlowFan1.jpg" border="0" alt="Photo Sharing and Video Hosting at Photobucket"></a>
So that from underneath, the fan blows up and across the bulbs...

You can use just paperclips to hold it on...

And so the air gets blown up and across the bulbs, then the acrylic sheild keeps the air flowing and ducted between it and the reflctors. The modification to the acrylic sheild is to open up the ends to accept air flowing in one and, and out the other.

The Teks can lose output due to heat... about 20%. The good news is that you can recover this loss by simply cooling the bulbs before its too late and the phosphors start to burn. Your first reading may have been right after starting the fixture, say 5 minutes. But after 15 minutes, the heat starts to build up after startup, and the output goes down due to heat... so you need to vent the heat. The above allows for that, as well as allows you to keep the protective sheild on.

 

[fijiblue]

Thanks for the help everbody. I wound up taking the acrylic off and raising it as high as it goes from the tank. Bought an azoo 4 fan unit on the back of the tank and blowing it towards the lights. Believe it or not, I am now running 42,000 lux at the surface...that's 1k more than with the lights all the way down. Keeping them cool really does make a difference.:furious: :hammer: