MH bulbs and a reef setup?

[fishtk75]

I read the MH posts that is on the other threads.
Sanjay's reviews and compared FAQ's
And saw and know it up to me as what color I like.
I need to know as a 250 watt MH 10k goes does it have more growing power as yellow or if it has more blue in it as a 12k, or 20k will make coral grow better? So a yellow, blue or very blue?
I am asking because alot of you members have more time dealing with MH for years and saw what works for you as growing corals.

[boxfishpooalot]

The more par the more growth will occur. Every bulb has a different par. Generally the yellower you go the more par you get.

Generally speaking, white light contains all the colors of the specturm and should have a very high par. As in light available to photosynthesis.

[maroun.c]

You can always supplement by an actinic or a white PC or fluorecent for your viewing preference. different lighting schedule during the day will provide for different viewing experience and you will have the more white or more yellow that yoru corals need to grow better. PErsonally I always had 20K because at the time that was all I can find and I got used to them with an additional 2 white marine flurescents and an actinic.
the view under actinics that I used to get at the last coupld of hours was great.

[Minotaur15]

I've always been partial to either a 6500k or 10k setup with the actinic support. Most light intensity and most available spectrum for coral growth. The blue lamps look nice, but I always preferred sticking with what is best for coral use. As the above poster said, use some VHO supplement to make it more astehetically pleasing. FWIW

[GreyDC]

10K's will get you your growth and you can supplement with VHO so more of your blues and purples pop.

A lot is dependent on you and what you want. Some folks want great coral growth and stick with the 10K's and VHO supp for the life of the tank. Others really want to bring out the colors of their coral so they go with the 14Ks or 20Ks.

I just experimented with different bulbs to see what I liked and to see what my corals liked it.......I started with 10K's w/ actinic on my SPS in order to get really good growth. Now I have switched to 14k's cause I wanted to get my colors to pop more........

Just my 2 cents though........

[Ritten]

I like the bluer look of the 20K. I switched to 10K to get better growth and it was just to bright for me. You will not get as good of growth with the 20K, but that works for me because my tank is full.

[boxfishpooalot]

Here is more technical I found from here:
http://forum.marinedepot.com/Topic67151-9-2.aspx







Also, just a few notes on using PAR with lamps of different spectral qualities and the effects on photosynthesis:

The way that photosynthesis works is such that every photon absorbed ends up confering the same amount of energy for photosynthesis. A blue photon, even though it is far more energetic than a green photon or red photon, confers the same amount of energy. All of the energy beyond what a red photon has is lost primarily as heat. For this reason a PAR measurement (photosynthetically active radiation) gives the same weight to every photon between 400 and 700 nm. A photon at 450 nm is much more energetic than one at 680 nm, but the two provide exactly the same amount of energy through photosynthesis so they get counted the same. The units for PAR (umol photons / m2 / s) is simply a measure of how many photons are hitting your sensor.

Unfortunately, photosynthetic organisms cannot absorb every photon between 400 and 700 nm with the same success. Once a photon is absorbed every photon is equivalent, but actually catching a photon varies depending on the wavelength. Since zooxanthellae produce both chlorophyll a and c2 and several accessory pigments they have somewhat broad absorption peaks. However, they absorb photons between about 400 and 500 nm especially well and have another peak around 680 nm. Between 500 and 650 nm or so they still absorb photons, but not as well as at other wavelengths.

What this translates to is the ability for a coral to actually use the light incident on it. If you hit a coral with light from an LED at 450 nm (blue) and another at 600 nm (green-yellow) and both lights have the same intensity (same PAR) the coral will absorb more light from the blue LED simply because it is better at absorbing blue light than green-yellow light.

To look at these kinds of issues (producing action spectra, looking at reflectance of the skeleton, measuring absorptance, etc.) to arrive at how much light a coral is actually absorbing from a light source requires much more sophisticated equipment than what you have access to and a heck of a lot of work (trust me). So, while PAR is not actually a perfect measure for comparing among lights with different spectral qualities, it's still pretty good and minimizing human error and standardizing your measurment protocols (as Eric mentions) is going to likely going to prove much more important for what you are doing. I mention all of this, I suppose, just so you have a better idea of the mechanisms underlying what you're measuring.

cj

[fishtk75]

Thank you all for your help now I have to input all of this that you all gave me.

[Frick-n-Frags]

the Iwasaki 400W is still the heavyweight champion of coral farming as far as I know.

Question: has anything more recent come up (I have been out of the loop for 2 years, so that's as far as I know I guess :D) regarding higher par than that Iwasaki in the 400W range without stepping up to 1000 watts

[boxfishpooalot]

The sun :)