I see all too many lighting type of questions on this forum. I am hoping this question is not as common as I could not find my answer reading through various old threads.
People commonly ask about lighting and is it ok for this and that. I see the occasional kelvin blurb in almost each of them but it seems to get dismissed very easily or overlooked as good information.
I am under the impression that not only is bulb wattage, mounting height, tank size, and coral depth important but so is kelvin when considering lighting questions.
I am one of the rare users of the Iwasaki 250W 6500k MH bulbs. I have been told for growth alone, there is not much better in the way of kelvin then 6500k. This is not to say that 10k, 12k, etc.etc. is not fine but they are more for coloration then growth. I guess many may debate this but it also is not the question I really have.
I do not get great polyp extension, at least not as great as I see others having with bulbs in the 10k kelvin and above range. This makes me wonder if my assumptions have all been wrong. Is the following too much lighting in my particular case?
75 gallon tank, standard four foot length. I believe it is about 20-24 inches tall.
2 x 250w Iwasaki 6500k MH bulbs mounted about 13 inches above water level.
4 x 110w Super actinic VHO bulbs. Two are mounted about 6 inches above the water and the other two are about 7-8 inches above the water line.
Water perams:
Ammonia = 0
Nitrite = 0
Nitrate = 0
Phosphate = no detectable amount
Magnesium = 1350ppm
Calcium = 410ppm
Alk = 8-10 DKH
Skim wet often
I just want to know if it is too much light for corals about 4-5 inches below the water line. I get decent growth, just not great polyp extension.
People commonly ask about lighting and is it ok for this and that. I see the occasional kelvin blurb in almost each of them but it seems to get dismissed very easily or overlooked as good information.
I am under the impression that not only is bulb wattage, mounting height, tank size, and coral depth important but so is kelvin when considering lighting questions.
I am one of the rare users of the Iwasaki 250W 6500k MH bulbs. I have been told for growth alone, there is not much better in the way of kelvin then 6500k. This is not to say that 10k, 12k, etc.etc. is not fine but they are more for coloration then growth. I guess many may debate this but it also is not the question I really have.
I do not get great polyp extension, at least not as great as I see others having with bulbs in the 10k kelvin and above range. This makes me wonder if my assumptions have all been wrong. Is the following too much lighting in my particular case?
75 gallon tank, standard four foot length. I believe it is about 20-24 inches tall.
2 x 250w Iwasaki 6500k MH bulbs mounted about 13 inches above water level.
4 x 110w Super actinic VHO bulbs. Two are mounted about 6 inches above the water and the other two are about 7-8 inches above the water line.
Water perams:
Ammonia = 0
Nitrite = 0
Nitrate = 0
Phosphate = no detectable amount
Magnesium = 1350ppm
Calcium = 410ppm
Alk = 8-10 DKH
Skim wet often
I just want to know if it is too much light for corals about 4-5 inches below the water line. I get decent growth, just not great polyp extension.
