Your favorite Metal Halides for Acropora Growth and Coloration

[Katrina71]

What I have always seen and been told, is metal halide light gets to where LED can’t. LED does a lot of shadowing where as the reflectors use by metal halide allow the light to “fill in” the shadowed areas. What I mean by this, and I do see it quite often at LFS’s, is in SPS colonies, LED only tanks the top of the colony is healthy but the bottom is white due to shadowing. At 1 hour, I honestly don’t know what impact it would have (I believe I’ve seen some charts (can’t find them currently) that show the photosynthesis period of coral for maximum light usage).

So will it have an impact, I think yes. Will it be significant, I honestly have no idea. Note that halides do not give a flourescent pop, so some coral that look fantastic under blues, could look dull and brown under a 10k halide. However here’s an example of coloration change in my tank:

Original frag: Purchased from an LFS using strictly LED: - July 2023

October 2023: In my tank

Again, I run 8 hours though, so I would imagine you’d have some impact

I'm curious to try it. I'm grateful for the breakdown. Should be fun to just try it and see!

 

[vetteguy53081]

Halides run hot and bulbs especially for hamilton units are very hard to find but they are the best effect on corals- mainly larger tanks

 

[dieselkeeper]

What kind of heat should I expect for an hour? Chiller or no? And how much would I need to expect it to impact my power bill? I appreciate your response very much. This is a Hamilton 10k Cayman or Bimini if I recall correctly, so small.

Having a fan blowing across the water surface, from side to side, helps out a lot with tank temp.

 

[Katrina71]

Having a fan blowing across the water surface, from side to side, helps out a lot with tank temp.

I planned on doing that too. Thank you!

 

[Reefering1]

So...my new build I plan on using MH for the most limited time possible at noon, I will also have led and T5. I just want to try the MH. What do you think is the minimum time you can get away with? Thinking heat and cost here. I was told even 5 minutes would make a difference. Input appreciated.

Good advice from @Reefing102 . I'll add to start at a hour or 2, led grown corals need to get used to the different light, and add another half hour to 1 hour a week if they aren't showing stress and heat is under control. Aim for 4 hours minimum. My tank(180g sys) takes a hour or 2 before temperature starts creeping up. I do use a chiller to keep tank under 79(ambient temp is about 78*) fans go a long way keeping it cool. As far as power consumption goes, consider it similar to adding another powerful led light(a little more than a xr30), because that's exactly what you're doing, adding another powerful light. I feel like I spend about a dollar a day between 2(true) hqi halides and chiller, insignificant in the grand scheme of things. What ballast do you have or plan on running?

Edit: if you use heaters, you can anticipate the heat and have them turn off a few hours ahead of time and let the lights do that work. If that's the case, that power consumption(of heaters) will offset consumption of additional lights

 

[reeferman]

Quick question....I have (2) brand new 250w Reefbrite single ended fixtures with RB digital ballasts, running their 20k twin arc bulbs. One fixture is producing the brilliant blue/white color you would expect, the other is producing an unattractive yellow/orange color. RB has replaced the bulb once but to no avail. Any chance the one color shifts closer to the 20k? The new bulb has been running for roughly a week. The previous one for 3 weeks before replacing.

 

[reeferman]

 

[RedoubtReef]

Swap the bulbs between fixtures or switch ballasts between fixtures and see if the right side still has the issue. It is the right side bulb, yes?

 

[bobnicaragua]

That looks like a 10k halide to me.

 

[minus9]

Swap the bulbs between fixtures or switch ballasts between fixtures and see if the right side still has the issue. It is the right side bulb, yes?

This! Also, pick up a kill-a-watt and measure what the ballasts are drawing.

 

[reeferman]

Swap the bulbs between fixtures or switch ballasts between fixtures and see if the right side still has the issue. It is the right side bulb, yes?

Thanks, yes it is the right side bulb

 

[reeferman]

To add, I had an older dimmable RB ballast running before I swapped to the brand new ballast, same color rendition.
I agree, looks like a 10k bulb to me. The first one and replacement bulb look identical.
I swapped ballasts to see what it looks like, will report back once they come on

 

[bobnicaragua]

I ran reefbrite twin arc 10k/20k for a while. I had 3 over my tank along with 2 orphek bars and 2 t5.

So the idea was at first the bulbs would light up 10k. Then turn them off for a few minutes and they should restart at 20k. That means for a few hours a day, you get the yellow light that makes your corals look brown and grow really fast. Then the 20k comes on for a whiter slightly blue look. Best of both worlds.

So, my acros took off. The problem was a lot of the time one of the halides would light out of order and I’d get a mix of 10k and 20k. Not a very good look.

I called Tullio and he basically said there was nothing to be done, the bulbs didn’t always light in the right order. They discounted them not long after.

 

[reeferman]

I have the 20k/20k so it should light 20k each time. The one on the left stays 20k, the one on the right stays about 10k.
After swapping ballasts, the color rendition is the same. I guess I will reach out again for a replacement.

 

[RedoubtReef]

I have the 20k/20k so it should light 20k each time. The one on the left stays 20k, the one on the right stays about 10k.
After swapping ballasts, the color rendition is the same. I guess I will reach out again for a replacement.

swap fixtures first just confirm the issue is not the ballast or the fixture.

 

[spsick]

Does this seem surprisingly low to anyone? @jda ?

Couple month old Phoenix 150w 14k in a Hamilton Cayman Sun fixture on a hammy m81 ballast. It’s drawing 1.7 amps on my EB8 but haven’t put it on Kill-a-watt to confirm yet. I have new Phoenix and some other used bulbs I can also test.

This is 16” below the fixture and 4” below the surface, measured with an Apogee SQ-420 (not-x) which is the same as original sq-210 but it’s just usb.

 

[jda]

420 needs results to be multiplied by 1.08. 200ish is fine with a spread type of reflector like that. You could probably get a more focused one and double that output over less area. Lower that fixture down until most of the spill goes away and then measure it again.

 

[spsick]

420 needs results to be multiplied by 1.08. 200ish is fine with a spread type of reflector like that. You could probably get a more focused one and double that output over less area. Lower that fixture down until most of the spill goes away and then measure it again.

Right on thank you!

It does have the immersion factor calculation option on the software which is on.

I’ll lower her down a couple inches a day. Started high because I figured it would be double that

 

[djf91]

Does this seem surprisingly low to anyone? @jda ?

Couple month old Phoenix 150w 14k in a Hamilton Cayman Sun fixture on a hammy m81 ballast. It’s drawing 1.7 amps on my EB8 but haven’t put it on Kill-a-watt to confirm yet. I have new Phoenix and some other used bulbs I can also test.

This is 16” below the fixture and 4” below the surface, measured with an Apogee SQ-420 (not-x) which is the same as original sq-210 but it’s just usb.

Why’s the water level so low? If the water was all the way at the top I would say it’s mounted at the right height.

 

[spsick]

Why’s the water level so low? If the water was all the way at the top I would say it’s mounted at the right height.

It’s a 40 breeder that I converted into an AIO with a big sump area on the right. Wanted it shallower so it costed less to light, heat, etc