14k/20k and coral growth

[lgray13]

I know this has been asked before cause I just got done reading a bunch of information and got a bunch of different "opinions". What I am trying to figure out is if coral growth will be slowed by 20k bulbs. I have 3x 250w MH on my 125g and right now have 3 different bulbs in, a 10k, 14k and 20k. These are all older bulbs I just wanted to see what the difference was before I order new bulbs. I don't like the look of the 10k, the 14k is ok and I really like the 20k. We were thinking about putting a 20k bulb on the two end lights and a 14k in the middle. I do not want to slow down the coral growth though and some said the higher k will slow it down and some said it just changes the color you are looking at not the par and won't affect growth. Does anyone know for sure? I have a mixed reef, softies, lps and sps. TIA.

[Goofishie]

Compicated question! Some Acros may be slowed by the red in the 10000K (according to Julian Sprung). Coral specimens from the shallows may grow faster with the low kelvin bulbs. Individual specimens are going to react differently regardless of what they do on "average". I think the 20k is the best, because the irradience will trigger the desirable color changes in the reactive proteins in the coral tissue (more phosphorescence). It also looks way cleaner and less yellow.

[Toddrtrex]

I can't tell you if it slowed down (( since this coral was always under 20,000K )), but I had zero complaints about its growth under 2*250 Radiums (( over a 58 )).

Started,



About 9 months later,

[tallreefguy]

It depends on the bulb & ballast. But I've always read the best thing for corals is stablilty. That includes light spectrum - because the corals will have to re-adjust.
Radiums give GREAT color. I run radium, Phoenix & an Elos bulb. Honestly, I prefer the Radium 20k to the phoenix 14k. It's brighter, better color. Growth is about the same.

As far as 20k slowing growth - check out PPFD readings @ Sanjay's site. An XM 20k has terrible PPFD / PAR readings (whereas an XM 10k blows almost everything out of the water), but a phoenix or radium have really good readings for the color temp. Remember that light is only 1 factor in coral growth.

My advise is go with a quality bulb (that has decent PPFD / PAR numbers) in the color YOU like, & keep your parameters stable - and the rest will follow.

[karsseboom]

If you go with radiums you need and m80 hqi ballast. That mean the bulbs will not run at the normal 250 watts but will really run at around 300 watts which will give some really great par numbers. Radium 250s on an m80 ballast is one of the highest par bulbs out of the 250s and in IMO the best color.

[mc-cro]

sorry to jump in and hijack this thread, but do radiums come in SE and DE versions?

[aandfsoccr04]

yes they come in both.

[sirreal63]

250's do not come in DE, only SE. The 150's are DE. If you run 250 watt Radiums, you should be using the M80 ballast but most electronics will fire them but will also under drive them, so you will not get the best PAR and color with electronics.

[TruespeedEM1]

What 10,14 and 20k bulbs are you using? Single or Double Ended?

The radiums do not come in a 250w DE.

I've had both 250w DE 14k Phoenix and 20k XM, and the 14k Phoenix is hands down better than the 20k. Better color and growth from the 14k compared to the 20k

[tallreefguy]

The Bluewave HQI ballast are M80's, right?

[sirreal63]

Yes, if you can find them. The AquaMedic Reeflex cube is also M80 and a good ballast.