20k radium: how blue

[LadyTang2]

If we compare to many of the LED lights, or say ab+

How blue would a 20k radium mh look compared to those and just in general?

I hate the actinic look but do like a little blue, should I back off to 14? or are both the 14 and the 20 white by todays blue obession standards?

 

[dadnjesse]

I ran 20K Radiums for years the color with an M80 Ballast is nothing like the Radion AB+ Led color much whiter.

 

[A. grandis]

If you use with the correct ballast it will show a nice bright bluish white. It's bright white with the blue hint. The correct ballast for the 250W Radium is magnetic M80. You can also use on electronic ballast dialed to "250W super lumens". It's not going to be as white, but close. I prefer to use the M80. Amazing bulb!!!!!!

 

[LadyTang2]

Will the 400w be bluer? or does that just make it brighter/more par?

How deep of a tank needs 400w?

Although I guess my power consumption will be alot higher with the 400.

 

[A. grandis]

You need to use the right intensity for the system's coverage and depth. We don't change intensity because of spectrum. 250W would be normally used for an ~18" deep tank. Different applications for different systems. One could use a 400W bulb with the appropriate fixture to spread light over a 12" wide frag tank if that fixture is far from the water. Depends on the setup.

 

[LadyTang2]

You need to use the right intensity for the system's coverage and depth. We don't change intensity because of spectrum. 250W would be normally used for an ~18" deep tank. Different applications for different systems. One could use a 400W bulb with the appropriate fixture to spread light over a 12" wide frag tank if that fixture is far from the water. Depends on the setup.

For a 30 inch deep tank, 400w then?

 

[LadyTang2]

Any other MH users to chime in?

 

[Bpb]

Which reflectors will you be using? That matters

 

[Silent]

20k is pretty white compared to the led look of today.

 

[LadyTang2]

Which reflectors will you be using? That matters

Not sure yet, maybe cayman/cozumel sun or ill just get the giesemann, some produce more blue?

 

[Bpb]

Not sure yet, maybe cayman/cozumel sun or ill just get the giesemann, some produce more blue?

No but if you use a larger/flatter reflector to cover a wider space you’ll want 400 watt bulbs especially to punch 30”, and if you use sharper steeper angled reflectors that are smaller and more deep set, 250’watt bulbs may be sufficient since they are more focused with less lateral spread

 

[A. grandis]

For a 30 inch deep tank, 400w then?

Yeah, generally speaking I would use 400Ws for a 30" deep display.

 

[A. grandis]

Not sure yet, maybe cayman/cozumel sun or ill just get the giesemann, some produce more blue?

The fixtures aren't related to spectrum at all. It only reflects the light you choose. Generally speaking the bulb's color ("spectrum", or kelvin number) will determinate how much white or blue you will get. The 10.000K is whiter than 14.000K and the 20000K is the bluest bulb available today. Many call the 10000K "crispy white", but some would call it "yellower", so... Different brands will have tones of white/blue a bit different to each of those numbers, but they will be kinda close. 20000K bulbs are pretty white in color comparing to the blue LED lights people use nowadays, and the 10000K and 14000K bulbs will have more yellow to it ("whiter"). You need to keep searching for pictures/videos of tanks with the bulbs.
20000K bulbs are what most people have.
You just can't go wrong with those!

 

[yeldarbj]

If we compare to many of the LED lights, or say ab+

How blue would a 20k radium mh look compared to those and just in general?

I hate the actinic look but do like a little blue, should I back off to 14? or are both the 14 and the 20 white by todays blue obession standards?

I recently switched from a 250w MH on electronic ballast to a pair of Hydra 26HD's. I mostly used Radium bulbs previously but tried many others over the years. First thing I did with the Hydras was try out the AB+ simulated spectrum and was shocked by how blue it is. It is so much more blue than a Radium. It makes the Radium seem like bright white. If you have a good reflector, the 250w MH is plenty for 24" deep (some sps at the bottom), if going deeper, you may want to go with 400w.

 

[Bpb]

I use 250 watt Hamilton 20k bulbs and get a range of about 250-400 par at 24” deep water with reflectors 12” off the water. This is what a deep reflector with a smaller diameter/width can do. But that spread is roughly 20” or so at that depth. I depend on overlap in the middle to make it usable for some lps at depth. But anything besides light hungry acros or clams would be burned at the sandbed directly under the bulbs.

On the opposite end if I used a larger more shallow reflector like the large Hamilton Cozumel sun, large lumen bright, or some of the bigger horticulture fixtures, Spread would be up in the 36”+ range at that same depth, but with 250 watt bulbs it would be so diffused that par levels would be lower. Diffused light is great until it’s not strong enough, which is why I’d recommend a 400 watt bulb if using a 20” or larger width reflector and punching more than 24” deep if you want a lot of acropora and clams

 

[LadyTang2]

How concentrated or shallow would you say the spectras are? Im guessing more focused higher par less spread, would you say thats true about the giesemann?

 

[A. grandis]

I have a 48" Spectra (they use SE bulbs) over my 75gal and use 250W bulbs. The spread is great as well as the penetration for my tank. One of the best fixtures on the market in terms of halide/ aesthetics. Unfortunately the T5s won't be as efficient as the ATI fixture. They don't have individual reflectors because of the "limited space" and no cooling efficiency. I guess we can't win all the time. But it will give you more than you need overall. It looks nice and clean.

 

[LadyTang2]

If I wanted to go MH only and dont care about how they look, which MH fixture would you choose for a 60x32x30?

Ive heard mixed things about some of the hamilton reflectors. Not sure on the reefbrite. Best fixturess?

 

[A. grandis]

If you don't mind bulkier fixtures, the Cebu is amazing. It has cooling fans, which is great!!! Hamilton is a great company, excelent customer service, and that fixture would be the one to get if you don't mind the littel noise of the fans and the box looking over your reef.
I would love to be able to run one of those over my system.

4 ft Cebu Sun Systems - 2 x 250 Watt & 4 x 54 Watt T5 HO

 

[LadyTang2]

Thanks @A. grandis , Why does it say 4x54, when its 4 on each side. I see 8 but on the site it does not say 8 anywhere, weird.

Also, if you were to go MH only no T5s which unit then? Reefbrite? Hamilton? Other?