[Reefland]

Here are the comparison shots between our 10k Ushio and AB bulbs and our new 20k AB Bulbs. Overall we are pretty happy with the coloration of the tank although it is going to take a little getting used to. I would imagine that after a couple of week burn in the bulbs will loose a bit of the blue we have now.

Tank lit with 10k Ushio and 10k AB:


Tank lit with AB 20k's:


Split image with the 10k Ushio and 20k AB:


Split shot of 10k AB and 20k AB:


Our M. digita under 10k:


Under 20k:


Scott Z.

[DukeDog]

I like the 20k's look . I have the 10k's myself but the 20's do look good.
Jeff

[Poseidon]

I like it Scott!!! Just seems "crisper" Hopefully you get a good layer of coralline on the bottom soon.

[SueT]

Hi Scott, I like the 20k's too. These lighting threads are so confusing. I switched over to 10k's in january and have now transferred them to my 120g and am seriously thinking about using 20k's on my 180g when it's ready for frags again. Meanwhile, I'm super happy with how frags are doing in the 120g under the 10k XM's.

I like the look of your digitata under the 20k, as well as the entire tank look.

[Reefland]

We like it too. These pictures were taken about 30 minutes after we fired up the 20k's and maybe it's just me but after about 3 hours of burning, they appeared a bit more blue than the picture represents in this thread. I'll get another shot in a couple of days to compare the two.

Mike,
The coralline algae is really starting to take off in the tank. If you look at my shots in my Documenting thread of when I first added the rock to today, you can see a quite a bit of difference already. The corals as well show signs of new growth already which is a great.

Scott Z.

[Poseidon]

Good deal Scott... Since I started with Mrs. Wages, I can't keep the stuff OFF my glass!!! I'm sure it'll grow like crazy for you too!

[Reefland]

Before the renovation, it was growing like mad everywhere but this is what I expected after the renovation; it'll be a little slow at start but the ALK and CA levels are in good shape so it will start taking off in the rest of the tank in no time.

Scott Z.

[Rp Marine]

what is your plan for the bare bottom?

[Reefland]

Lots of flow and siphonings with each water change.

Scott Z.

[zhenya]

Hi Scott,

I do like the look of the 20K as well,however, you are correct in that it is too early to tell. It'll all boil down to how your corals will do and if you'll be pleased with the growth.
How is the PAR of the 10K and 20K DE bulbs compares?
FWIW, the greens will look super green under the 20K and purples as well...good luck and post some more pics as they burn in some more.

[Reefland]

The PAR is the part that scares me. Based on other 20k tests, I am sure the AB 20k's will be lower in total par than the 10ks but I am hopefully growth and coloration will be fine.

Scott Z.

[JB NY]

The pictures look good Scott. I haven't seen the DE AB20K in person, but those shots make it look nice!

[Tie]

Wow.. great thread and pics!

It's funny I ran across this. I just ordered 20K to replace the 10K's that are barely broke in.

The reason. The guy at Reefermadness convinced me that all the "sun grown" corals that I eventually want to add to my tank would hold their color much better under 20K.

He told me that tank cultured frags do fine under the 10k as they where "born" under the lighting so what ever color they develop under that lighting they would be able to hold. However, he was adamant that "sun grown" wild corals would loose color under 10K.

He also said that 10K do great for soft corals and are better as far as growth but hard wild grown corals would suffer color loss.

As for burn in. He said he runs 20ks on all his tanks and has for a long time. He said that after a few weeks they would actualy be less blue then they are at first.

The end of the matter for me. If I wanted a tank full of softies that have less color for the most part anyway then 10k is great. Also, if I have a tank full of frags hard or soft that where spawned under 10k no problem. But I like the acro's and other hards and that's going to be my main focus. Further I don't mind paying a little more for the larger brilliant "sun grow" stuff. I'll have fun with frags LATER down the road when I get my 250 going but right now I want em big and colorful. Hope this guy is right... lol I put a lot of stock in what he said.

[zhenya]

Tie,

I'm not sure why guy from reefermadness brought up sun into comparison with the 20K bulbs. I always thought that the closest bulb to the intensity and spectrum of natural light was the Iwasakis at 6500K and I'm sure that many reefers still use them. Complimented with the actinics fluorescent bulbs it is the best bulb in my opinion,hands down
Then comes the human eye and how we percieve light...and here comes the 12,13,14 and the 20K bulbs outta woodworks
Not to sound contradictive or knock down 20K bulbs, if you like them then use them,however,I'm sorta lost where sun and 20K bulbs come close.
I got few articles for you,if you inclined to read them.Perhaps you already have but I'll post them for benefit of others who hasn't yet.
http://www.advancedaquarist.com/issu...03/feature.htm
http://www.advancedaquarist.com/issu...02/feature.htm
and this article I think explains alot better then what I had said previously

[Tie]

Yeah, those are some good articles. It really is confusing and in my mind no clear answer as to what is the "best" exists. The problem is perhaps as they stated "the "best lamp" means different things among hobbyists"

The "Spectrum or Intensity" was interesting and it sounds like they more or less concluded that spectrum made little difference as far as photosynthesis was concerned.

The problem I see is they said.
"We did not conduct measurements of absorbed PPFD but we made the assumption that the pigment content of the coral’s zooxanthellae did not change during the experiment. Thus we report the "relative" ETR (not the absolute ETR)."

And that's the point I'm most concerned with aside from photosynthesis. Long term effects on pigmentation. They assumed there was not pigment change and perhaps there was not any visible change during their tests. But I guess my question is, "what long term effect does spectrum have on pigmentation". No doubt the effect would mean different things to different corals.

The only thing to go on at this point is "perceived" results from people who have used different spectrums over time. I don't have any experience so all I can do at this point is listen to what others say they have experienced. I do realize that going outside the realm of facts and leaving it to "perceived" results will leave me with 300 different opinions and no real answers.

So, that said. What is your opinion based on your experience? 10K vs 20K. The question: will wild caught hard corals.... say for example A. Rosaria loose some of their pigmentation or color under MH 10K lighting with supplemental Actinics vs 20K MH with the same Actinics? Way speculative question I know. Just looking for some broad opinions based on what you have seen.

[zhenya]

Hi Tie,

The problem I see is they said.
"We did not conduct measurements of absorbed PPFD but we made the assumption that the pigment content of the coral’s zooxanthellae did not change during the experiment. Thus we report the "relative" ETR (not the absolute ETR)."

Well, in my opinion they were correct in their assumption that pigmentation of the zooxanthellae had not changed. It is what it is and as far as I know its pigmentation is brown or golden brown(whatever that means). Other colors that we see most likely from the fluorescing proteins of the coral that it is using for protection against some of the UV radiation.
I do not have many wild corals,only a couple and I was able to keep their original coloration under the 10K bulbs. I did experiment with the 20K bulbs as well and noticed some corals color up more(to my eye that is) and then some did not show any change at all.I must add,however, that those 20K bulbs did luck in PAR if compared to Ushios.This brings me to my point, what is more important,intensity or the Kelvin number? I really think that if bulbs has enough intensity for the coral to reach its saturation point(for the zoxanthellae) then it should be irrelevant if spectrum is higher then 6500K.
I also like to add that I don't know enough about it to argue about lighting and rely solely on the information provided by people who really knows,like Dana Riddle, for example
I also think that lighting alone does not play exclusive role in coral coloration but rather that it works in combination with water chemistry.JMO,mind you.
I had noticed more color changes with different Alkalinity and Calcium numbers then I did with different Kelvin bulbs

PS. I also forgot to add that many colorful Acropora species are found in rather deep waters where I'm sure they do not recieve full intensity of the sunlight, which makes this argument about lighting even more confusing

Scott, I'm sorry if I helped in derailing your thread

[Reefland]

No apology required; we all love a good discussion.

I think your right in your quote that the "best lamp means different things to different hobbyist". Reason being is that there are 2 different goals for hobbyist; an aesthetically pleasing display tank or a functional propagation system where growth is the focus.

Depending on the choice of these 2, the coral the aquarist is interested in displaying/growing plays the most critical role in lighting schemes. Since we're talking about Metal Halide here and most of us are interested in SPS corals, we will choose SPS corals for the sake of deciphering the other 2 choices.

If I were to choose an aesthetically pleasing display tank, which I have, I opt for color over growth (notice say over growth because we still want our corals to grow to display our success) which means great coral coloration and a display with overall color that is pleasing to the eye. For both this typically means some degree of "blue" coloration which is a bit more natural to the eye and the "blue" light seems to help the corals flouresce their coloration more. So we definitely want some blue in the mix which means 6500k with very heavy actinic supplementation, 10k with a bit or 20k with none. There haven't been any official studies that I am aware of conducted to prove which kelvin temperature bulb provides the best coloration, I am going strictly from internet discussions here.

If you are going for growth, aesthetic appeal is out the window and your looking at natural sunlight or 6500k. Obviously natural sunlight is great for growth and again through the time spent on the internet, 6500k's are great for growth as reported by our fellow hobbyist.

Back to my decision; I know that I am taking a loss in PAR by switching to the 20k DE bulbs, but the studies done on the 10k DE bulbs show more PAR produced over 10k mogule base bulbs of the same wattage. With that said, I can only assume that the 20k bulbs are producing PAR that is at least equal to what 10k mogule bulbs are. Just a guess. We know that we get good growth from 250w 10k mogule base bulbs, so I should get a bit of both worlds in color and growth out of my 250w 20k DE bulbs, without the added expense of supplementing my 10ks with actinics.

Just some random, very unorganized thoughts. I'm at work, give me a break.

Scott Z.

[zhenya]

Originally Posted by Reefland

There haven't been any official studies that I am aware of conducted to prove which kelvin temperature bulb provides the best coloration, I am going strictly from internet discussions here.

Scott,

I'm not sure if exact studies were done or not( I don't see why it would since coloration is not a primary concern in reef related studies ) but, I think enough studies were conducted to make conclusions safely that Kelvin numbers are mainly for the hobbyists to ponder
FWIW, I don't knock your choice of bulbs by any means,in fact I think your tank looks very pleasing to the eye and I'm sure your results in growth and coloration will be very good as well.
If I'm ever to have that larger tank, this thread gives me a chance to watch your tank grow, providing that you won't slack off on picture taking and posting... and make my decisions on lighting scheme then.

[Reefland]

Here is an image 6 days after the 20ks were added.



For the sake of comparison, here is the same image as the post above when they were just added:

[zhenya]

Looks really nice,Scott. However, I did not notice much difference between two pictures, probably due to my bad eyesight
I did notice that you had moved one of the corals a bit higher,though