10k or 20k XM bulb

[TruonkQ]

i got 2 x 6' vho's URI, 3 x 10k MH on my setup now and wanting to know would it look better if i switched to 2 x 20k and leave the center one 10k?

[brewercm]

Are you running single ended bulbs and what ballasts. Just from my experience I loved the 10K SE bulb on the electronic ballast. It looked very white with a hint of blue and the URI Super Actinics with them were a perfect setup in my opinion.

[TruonkQ]

yeah se xm's w/ URL electronic ballasts. does the 20k bring out more color to the fish?

[brewercm]

I don't think that it really brings out more color to the fish but it can bring more color out in some of the corals. But as long as you are running the URI super actinics your corals colors will look nice anyways. Possibly even add more actinic if you have the room.
Once again these are just my opinions.

[caferacermike]

As long as the topic is 10k or 20k, and not to hijack here or anything, besides color enhancement what is the real difference? One author will say that corals grow super fast in the 10-12k range as that is natural sunlight, then another will say that 20k bulbs grow coral even faster as it's like "super" sunlight. I'm running 20k double ended bulbs and some that I have spoken with say I should change to 10k's and change my PC duals to straight 20K and my corals will grow much faster and my tank's colors will be the same.

[brieman]

I have 20k and 10k on mine, there is a big difference in the the color but there is no noticable difference in the way the corals or fish look under the 20k. I myself am looking into getting the super actinics.

[TruonkQ]

I've got a friend that runs 3 x 250w de 20k's and the fish/ corals look really nice. Going back and looking at my big tank w/ 3 x 10k's looks kinda too bright white. It doesn't really bring out the color on the yellow tang, but that may be because i don't have a black/ blue background. I've also liked the color when i run my vho's and just one 10k. I've seen at one of the LFS in houston running 4 x 65w atinics and 3 x 10k's that looks really nice. Should i just add more PC's or switch to some 20k's? My electric bill is only $350 a month =0 LOL.

[Jeff]

20k gives great color to your corals but is low on PAR, so slower growth. 10k good color, good growth because of higher PAR values. 6.5k no color, but great growth becauese of highest par value but low color spectrum.

[alton]

DE 20K and SE 20K are not the Same. I have used 14K DE and they look like 10K SE. CB pets has 20K DE on there coral tank and they don't look blue at all like a SE 20K would look. The fun part about this trade is having too many choices. A few years ago you had two choices an 03 and 3 cool whites or a yellow MH.

[GaryP]

My only problem with the 10Ks are that they seem to have some quality control issues. I have one that is very yellow and I get very little growth from that end of my tank. As was mentioned you give up a lot of PAR with the 20Ks. The other thing about XM 10ks is that while you get great 420 nm (purple) light from them, you get very light 460 nm (blue). Likeise, you are not getting any 460 from the actinics. While I have been a big proponent of the XM's here in the past, I'm currently looking for a more full spectrum bulb for my system. The XM 10Ks also have one of the best PAR ratings out there, but because of the QC problems I mentioned before, I'm starting to think this is hit or miss.

Maybe we can Jim Norris to jump in on this one. He probably knows more about XM bulbs then anyone here.

[brewercm]

As far as your tank and the question about adding more actinic. My personal opinion would be to ditch the PC's and load up as much URI Super Actinic VHO bulbs as possible and run that with the 10K MH bulbs and I think you'd be very happy. I was amazed at the difference when I changed over from my old PC's to the VHO and the quality of the actinic look. I myself need to add two more actinics to my system, at least I think I do but my wife doesnt' for some reason.

[saltcreepette]

I agree with what jeff said, and I have also heard, like Gary, that the XMs can be inconsistent. I myself have 2 of the XM 15K SE bulbs and like them (I have no supplemental actinic, soon to change), and theyve served me well, however I look forward to going with 10K's and adding pc actinic. My fish look great right now, and my corals look pretty enough, but I know their colors would be shown off more by adding more actinic than my current lights. Right now, especially in the first 30 minutes, my tank has a not-extreme but noticably blue cast if I pay attention. To summarize, I think I have not enough intense blue, too much washed out blue, and not enough white (I hope that made at least some sense). If I were you and not satisfied with what you have (it just might be that THREE 10Ks is too bright!), I would do the 10K in the middle and 15K's (not the 20's that'd be too blue) on the ends, and use the vhos for actinic.

[TruonkQ]

i think i might need an extra 2 x 8 ft. vho's actinics. Maybe it would help blind me more =) so i could stop buying fish/ corals. The 2 vho actinics i got already makes my tank purple. So with two more it would be worse, but ill just make that one a switch on for show only i guess.

[Richard]

If you get 4 vho bulbs then you can use 1 or even 2 actinic white bulbs along with the super actinics to balance out the blue a bit. The actinic white bulbs are a 50/50 type bulb (10k and actinic phosphors). So your corals would still get more actinic light and you wouldn't have to stare at a totally blue tank.