400w MH spread?

[ZaneTer]

Hi everyone,

After having been away from the hobby for about 18 months I have decided to get back into it.

I don’t have any experience with metal halides but I would like to know if a 400w would be enough to light an area of 3ft x 3ft?

thanks
Zane

 

[Viking_Reefing]

Welcome back. With halides it has a lot to do with the reflector. What kind will you be using?

 

[ZaneTer]

I’m undecided, I end up spending a fair bit on heating most of the time which prompted the thought of going MH.

 

[BigKid4788]

I have a 30” wide tank and my MH sits about 14” above the water and has plenty of spread. Since you are running 400w, you can raise it to get better spread if needed.

 

[polywise]

I have 4 400's over my 48x48 tank - SPS

depends on what you are looking to do.
I think there will be visual fall off towards the edges.

Jim C.

 

[ZaneTer]

Thanks very much everyone, much appreciated

 

[bobnicaragua]

You could do a halide in the center and led or t5 bars on the outside.

 

[ZaneTer]

It is going to be a very slow build over the next 18 months or so. Overall I am after a 6x3x2 or roughly 270g.

I will start a build thread on it once I get the frame, sump and tank ordered.

 

[brick-brothers]

This was tank before I took a break from the hobby 5yrs ago. I was running 3 400w MH with Lumen Bright Reflectors. 20k Radium Bulbs. Best growth I ever had for as sps. I just started back up also 6mo ago using the same lights. You cant go wrong with them

 

[theocorals537]

Thanks very much everyone, much appreciated

Hope your doing well! Are you considering single ended bulbs or double ended? Single ended are cheaper , and more color options but don’t pack the punch that the double ended bulbs have. The singles also don’t reflect as well.

 

[DonTavo27]

I’d say 3 400watt radiums would be perfect for the dimensions you’re gong with.
That and a couple of SB LED Bars would make a great combo.

 

[ZaneTer]

It’s going to be a fishless system so intend a fully enclosed and reflective hood along with the back, left and bottom panels all with a mirror finish. Because of that I am very cautious to use more than 2 lights unless a par meter says I need to.

It sounds odd but I am not wanting any rock or stone in the display. All of that will be contained in the sump.

This is intending to be a 10 year tank that hopefully ends up wall to wall corals and nothing else.

At least that is the dream.

 

[oreo54]

It’s going to be a fishless system so intend a fully enclosed and reflective hood along with the back, left and bottom panels all with a mirror finish. Because of that I am very cautious to use more than 2 lights unless a par meter says I need to.

It sounds odd but I am not wanting any rock or stone in the display. All of that will be contained in the sump.

This is intending to be a 10 year tank that hopefully ends up wall to wall corals and nothing else.

At least that is the dream.

You need some "data"really.
Old school wpg say 4-8/gal.
Meaning about 1000-2000 watts.
Using "300watts".
Metal halide

Quantitative Comparison of Lighting Technologies: Metal Halide, T5 Fluorescent and LED

Based on this quantitative data, is its quite obvious that the LEDs have come of age in providing a viable solution to lighting reef aquaria.

reefs.com

Obviously different lights/reflectors different results but staying in class should give a general idea.
Point being 2 400's is probably minimum for your needs depending on height/depth though.
30" from bulb to substrate @ 400 W looks adequate to push the 200 plus par.

A 250W double ended USHIO 14000K lamp in a Sunlight Supply Lumen Max 3 reflector driven by a “HQI” M80 ballast was used a representative of the class of metal halide lamps. Figure 1 below presents the light distribution for this combination. Peak values of PAR achieved were 278 micromoles/m2/sec at distance 24″ from the center of the lamp, and 190 at 30″ from the lamp center. Interestingly, the peak values are not directly below the center but offset from the center. The power consumption for this combination was 306 Watts

 

[infinite0180]

I keep reading that the 250w Radium run on a Hamilton M80 will actually be about 330w and very close to the 400w Radium as far as performance. I personally would go that route and skip the 400w set up...

 

[ZaneTer]

I think the best thing I can do is mock up a test hood with Mylar lining and get a par meter for testing. I will have to factor in losses through water but it should give me a rough idea. Ultimately if it doesn’t provide enough par I will add another fixture.

I will keep everyone posted.

 

[oreo54]

I think the best thing I can do is mock up a test hood with Mylar lining

You want to get real "technical" just use Barium sulfate paint.

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1010&context=cpl_techniquesinstruments

Mylars not bad..

https://www2.cose.isu.edu/~mcnudust/publication/presentations/MOLLERCollabMeeting_2016Apr30_refTalk.pdf

Summary and Future Plans•Materials with silver are poor UV reflectors•

Materials with silver more sensitive to radiation although all reflectors tested seem robust (even the 1 mil al. mylar)

New Barium Sulfate-Based Paint is Whitest Yet | Sci.News

The new barium sulfate- (BaSO4) acrylic paint has a solar reflectance of 98.1%, according to a paper published online in the journal ACS Applied Materials & Interfaces.

www.sci-news.com

 

[ZaneTer]

You want to get real "technical" just use Barium sulfate paint.

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1010&context=cpl_techniquesinstruments

Mylars not bad..

https://www2.cose.isu.edu/~mcnudust/publication/presentations/MOLLERCollabMeeting_2016Apr30_refTalk.pdf

New Barium Sulfate-Based Paint is Whitest Yet | Sci.News

The new barium sulfate- (BaSO4) acrylic paint has a solar reflectance of 98.1%, according to a paper published online in the journal ACS Applied Materials & Interfaces.

www.sci-news.com

Thank you, that’s actually a very interesting read. I am a little undecided. I prefer a mirrored look for the side and rear panels adding to the illusion of more space although 270g should be plenty of space. For the hood and bottom of the tank I don’t mind what I use.

I already have Mylar from...another project.