reefmutt
Active member
Mike, in my tank, apart from 1 coral which couldnt deal with the high PAR in my tank, all others are fine. I did acclimatise the SPS over many months with my old T5/LED unit.
As Matt suggested, slowly increase the PAR over 4 weeks. No more than 5% each week. Since you are at 60% now, in 4 weeks you should be at 80%.
The nutrient level in the tank should be at a stage where you are needing to clean the tank glass about every 3 days. Ensure there is detectable PO4 and NO3.
The spectral signature of the Radium bulbs is proven to be most suitable at colouring up SPS corals. I would try copy that spectrum? I would definitely run the UV and 455nm Royal Blue at full. The other two blues I would run a lot lower. This is where my suggestion differs to what Matt is advising. Matt has actual experience with this light so maybe go with his advice.
However, initially you can try keep the UV and Royal Blue at full, and then adjust the others to try and mimic the Radium spectrum as best as possible and see how the corals respond. After that, try boosting up the other two blues to maximum as advised by Matt.
Here is the spectrum I am running in my combo of T5 and LED:
That is a combo of 4xATI Blue+, 1xATI Actinic, 2xATI Purple+, 1xKZ NewGen and the LED's at various intensities (RoyalBlue, Blue, White and Red).
That combo as you can see, has a decent Actinic spike, a massive spike around the 450nm area, spike at 545nm (green), 575nm (yellow) and a decent amount of light in the orange to red area.
Can you describe some of your SPS colours? Which colours are good? etc?
My motivation for designing light programs has always been based on the assumption that it is the blue end of the spectrum, including true uv (below 400nm) that travels the best and farthest through water. As the spectrum goes higher through green and yellow, the light doesn't really penetrate very far..
I have always assumed that because of this, corals have probably adapted to utilizing this area of the spectrum the most.. This and the fact that blue bulbs seem to colour up corals best is why I always run my blues at full.
I also believe that an element of true uv is important to properly colouring up sps.
Xm or radium bulbs contain a fair amount of uv in their spectrum.. As well as the full range of uv/blue colour range..
Sahin, just wondering why you would suggest lowering certain elements of blue in the colour mix?
Something else that occurs to me is that t5 and mh bulbs produce light in a very comprehensive way; they emit a full palette of colours with peaks in certain wavelengths, depending on the bulb. It is my assumption that LEDs do not do this. From what I have gathered, LEDs produce very sharp and narrow colour ranges that would look like sharp spikes on a spectral graph as opposed to the smooth waves of varying colour ranges you see on a spectral graph of a t5 or mh.
This is why multiple LEDs are required- to fill in as many gaps in the spectrum as possible..
I always assumed that when led companies produce a spectral graph of their lights, it is slightly misleading that the graph looks like smooth waves. It should really look like very sharp spikes at specific nm points relating to the specific LEDs used..
I believe that for this reason, sps in particular (I have no idea why only sps) have a hard time using the light emitted from LEDs. Maybe it's because they are so close to the surface of the water where, in fact, most areas of the light spectrum are still penetrating the water. Maybe they really need a true full spectrum but still rely on the more blue elements to achieve strong coloration.
As for using k temp as a way of replicating spectral output, I also think that this is tricky... Using the control centre, one can mix the blue LEDs in many ways to achieve a value of 20k... Or any k value for that matter. I think there is some, obviously, but not a great correlation between k temp and spectral output..
I know that this is long winded and based ONLY on my 'google knowledge' since I have no background in light dynamics but I think it's worth noting..
And if I've said something that is inaccurate, please correct me. I'm here to learn and share information..
