Yet another lighting question

[spaulr]

A little background on the system. I currently have a 150W DE metal halide PFO fixture with a 150w icecap ballast and 2 39w t5 actenics. The halide bulb is a Aqualine AB 10k.

I really like this light because it is amazing bright, crisp, and white...not to mention the really good coral growth I've been getting . However, I've decided that I like the tank with a bit more blue to bring out coloration of my corals. I recently bought a phoenix 14k bulb to try and help things out a bit.

After swapping bulbs I can't believe how much dimmer the light is :?. I was careful to read the reviews and the PAR outputs were fairly close (I thought). Maybe I bothed that up somehow. It seems like if I want to use a 14k or 20k bulb I need to step up to a 250w light in order to get the same intensity (brightness) in the tank. Does anyone else have this type of problem when going to a higher Kelvin bulb? If so, how did you solve it?

 

[shavo]

I disagree with your post. I have a 150 watt DE 14K bulb and my buddy has a 14K 250 watt MH, the brightness I think is exactly the same.

 

[LA-Lawman]

I have run both the phoenix 150w de and the 250w de. I saw no difference. mind you. i ran them on tanks appropriate for the bulb wattage. the 250w has the punching power for the taller tanks.

i really like this bulb. I am going to use it on my grow out system i am building.....

 

[spaulr]

The 150W I have is centered on a 40 gallon. Most of the light is centered in the middle so I can put some softies on the edges.

I guess I'm a little confused about the responses. I have no experience with a 250W lighting system, and was only suggesting that going to a higher wattage output on the same tank might solve what I consider a brightness issue or output issue when using a higher Kelvin bulb.

If higher wattage bulbs have more penetration power in water (IE more light at a certain depth), then clearly they should be "brighter" at the same depth than a 150W bulb? Maybe I shouldn't say brighter, krap.....My tank looks a little dim with the 14k...don't know how else to explain it.

 

[ChrisRD]

Running the same type of lamp on the same style ballast, the higher wattage setup will be brighter.

Keep in mind, the ballast is a big factor. Most DE lamps will not be properly driven by an electronic ballast and will appear dimmer than they should. DE lamps are designed to be run on ANSI M80 (for 250 watters) or M81 (for 150 watters) magnetic ballasts.

 

[spaulr]

Thanks Chris. That's what I thought. Although I did not know that little tidbit about the magnetic ballast. I'm going to assume that the DE bulb is being underdriven by the ICECAP electronic ballast I'm using? Hence the decrease in power consumption (IE power savings)?

 

[ChrisRD]

Yes, that's very often the case with DE lamps (ie. the eballast will run the lamp dimmer and consume less power) although there are some exceptions to that - particularly with the 150 watt lamps. In fact, the AB 10K you were using is one such exception (runs very well on eballasts). I use the 250 watt Phoenix lamps and they run brighter on HQI than eballasts, but I have no experience with the 150s so I'm not sure if it's the same relationship with the lower wattage version.

That said, the Phoenix lamp likely puts out less PAR on any ballast than the AB 10K you were using before and that is probably the largest part of the issue. In addition, being a bluer lamp, the Phoenix won't appear as bright to your eyes as a lamp that has more output in the yellow/green spectral range (like a 10K) where our eyes seem to be more sensitive.

HTH