10k or 20k MH

S

spsaddict

Guest
used the 20k xm for 1 year. i love the color but i was really dissapointed that alot of my corals turned green... i got decent growth from them as well..
i now use ushio 10ks love em great growth... once i get my 400w ill be going back to the 20k
but it all depends do you like a bluer look or a crisper white
 
kc36330

kc36330

Member
my 180g has 20kk's 2x400w and 2x250w, like spsaddict some of my corals have turned to a more green hue.
over my 29g i have 1x250w 10kk and i get a more yellow hue from corals.
hth
kc
 
kc36330

kc36330

Member
IMO/IME corals use the pigmentation in their flesh to absorbe/reflect light to get/reject portions of the light for their own needs.
most corals will brown up when lighting is low in order to absorbe more light from different spectrums. when in an overly abundant amount of light, they bleach to reflect it back away.
under the 20KK's they dont turn to a pure green but get a more green hue to most of them (mostly my acros) yellows seam to get more intense and purple gets a more blue look.
hth
kc
 
S

spsaddict

Guest
actually all sps are brown and they get there color by using protiens used to sheild them from certain aspects of the lighting spectrum. the lights we use empahsise certain spectrums more than others to get the corals to glow more... hence the colors we see
 
kc36330

kc36330

Member
6-10 hrs on average depending on the corals you keep and a few other small variables. using your corals visualy you can most often tell if they are getting enough lighting.
kc
 
neowind

neowind

Member
I use 175w XM 20k bulbs and run them for 12 hours a day. You want to mimic the daylight cycle of where they would normally live.
 
kc36330

kc36330

Member
there has been a lot of research over the past few years about coral growth in relation to lighting. while in nature tropical areas have 12 hr daylight cycles, corals do most of their calcium uptake after the first 3 hrs of light and start to drop off considerably after 6 hrs (this is in their natural/optimal lighting). the deposit and hardening of the skeleton is done during the dark hours for most SPS.
taking that information I ran a 6 hour on/off photo period on my 180 for 6 months. the tank has 2x400w and 2x250w XM 20KK's. the growth of SPS and most softies seamed to improve a fair amount, but the fish seamed considerably more stressed. I guess they were getting 'aged' twice as fast in their 'minds' as well.
I now run an 10 hr on 14 hr off scheme and everyone seams to like it, myself included.
kc
 
kc36330

kc36330

Member

Originally posted by spsaddict
your 400s what brand are they?
the 400's as well as the 250's are XM 20kk's
kc
 
kc36330

kc36330

Member
I guess it's just a matter of the reefers own opinion and eye appeal. myself I like the more deep water blue look of the 20kk's. when I ran 4x65pc over my 29 they were 3 actinic to 1 daylight.
the 29 now has a 250w 10kk MH with no actinic and it's defiantly more white then before. I don't dislike the white but I prefer a more blue just don't want to add more lights to the tank for supplementation.
kc
 
robchuck

robchuck

Active Member
I like the looks of the 12,000K-15,000K bulbs; not too blue, not too white. The PAR values are lower than some of the 6,500K and 10,000K bulbs, but I can live with that.
 
kc36330

kc36330

Member
it's a give/take kind of thing. with 6500K bulbs you get the most par but you get the worst color for a tank IMO. with 20KK's you get far less par but much better eye appeal (at least to me). 10KK's are a good compormise esp if you use heavy actinic's with them.
kc
 
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