Metal Halide - 14k vs. 20k

[socalmonty]

I have heard from enough people that coral growth is much better with 14k MHs so I'm thinking about a change. My 135g tank (60"w x 30"t x 18"d) currently has two 400w 20k single-ended MH and two 110w VHO actinics. Nothing seems to grow very fast (not even zoas and palys). The tank has been set up for a bout a year. I'm thinking about switching to 14k MHs. Any thoughts on the conversion? I have mostly LPS and softies with just few SPSs (mostly montiporas). Can I just switch out the bulbs or do I need to reduce the light for the conversion period? Best brand of bulbs, etc.? Thanks.

 

[thegrun]

You should either cut back on the photo period or shade the tank with screens when you put in the new bulbs. The 14K should give you a little more growth as it is closer in color to natural sunlight, although many get good growth from their 20K bulbs. If your bulbs are a year old they need replacing and that alone could be the reason you do not get good growth.

 

[savethereef]

also besides you lights you need to keep all parameter on check. i have been running 14k Phoenix for about 5 months now. And since i got a Calcium reactor just 1.5 months ago corals have grown 5x time faster than before. Also i run my lights for only 4hrs/

 

[krucial]

If you want growth it is best to put 10k bulbs for some time. They are not the ideal light that makes your tank look beautiful, but it does enhance growth a lot more. Just like thegrun said, switch your bulbs once a year, every ten months would be even better.

 

[socalmonty]

Thanks. I switch my bulbs every six months. My current bulbs are only three months old. My tank parameters are good and pretty stable, I think. SG 1.025, MG 1425, CA 425, Alk 10. I dose four drops of Lugol's twice a week and do a 15g water change every week. But still not much zoa growth. I want a zoa garden but so far it's not happening...

 

[cyberseer]

<a href=showthread.php?s=&postid=14900241#post14900241 target=_blank>Originally posted</a> by socalmonty
Thanks. I switch my bulbs every six months. My current bulbs are only three months old. My tank parameters are good and pretty stable, I think. SG 1.025, MG 1425, CA 425, Alk 10. I dose four drops of Lugol's twice a week and do a 15g water change every week. But still not much zoa growth. I want a zoa garden but so far it's not happening...

Why dose Lugol's?

 

[thegrun]

It does sound like a lighting color issue with all your parameters in check.

 

[socalmonty]

My xenia and leathers seem to do better with the Lugol's. I also had heard that it was recommended for zoas. Is that not right?

 

[socalmonty]

<a href=showthread.php?s=&postid=14900520#post14900520 target=_blank>Originally posted</a> by thegrun
It does sound like a lighting color issue with all your parameters in check.

My tank is pretty deep (30") so that's why I am thinking the 14k might do a better job for the corals in the botom half of the tank. Is that a misconception?

 

[socalmonty]

<a href=showthread.php?s=&postid=14899970#post14899970 target=_blank>Originally posted</a> by thegrun
You should either cut back on the photo period or shade the tank with screens when you put in the new bulbs. The 14K should give you a little more growth as it is closer in color to natural sunlight, although many get good growth from their 20K bulbs. If your bulbs are a year old they need replacing and that alone could be the reason you do not get good growth.

thegrun, when you mention screens, what kind of screens are you referring to? Like a plastic mesh screen you would use in a window frame that I could get at a hardware store? How many layers should I start with and how quickly can the layers be removed? Any help would be greatly appreciated.

 

[d34532]

I think those screen at say hd has different grade of light that it blocks. You can do 2 maybe 3 and take it off one every 5 to 7 days. I just lower my photoperiod and raise it up slow like 15min per day over 2 weeks time.

 

[socalmonty]

<a href=showthread.php?s=&postid=14937732#post14937732 target=_blank>Originally posted</a> by d34532
I think those screen at say hd has different grade of light that it blocks. You can do 2 maybe 3 and take it off one every 5 to 7 days. I just lower my photoperiod and raise it up slow like 15min per day over 2 weeks time.

Thanks, Lam. I may try some of both, just to be safe. I have heard nightmare stories about folks losing lots of livestock in the switch. Today is the day. I'm crossing my fingers...

 

[speargunhunter]

Metal Halide - 14k vs. 20k

<a href=showthread.php?s=&postid=14900705#post14900705 target=_blank>Originally posted</a> by socalmonty
My tank is pretty deep (30") so that's why I am thinking the 14k might do a better job for the corals in the botom half of the tank. Is that a misconception?

my tank is 58x30x30 im using 2x250 DE phoenix 14k for 4x day also 4x54w suplement morning/evening.
i have sps on the top and many zoas on bottom growing like weed in it, sps has decent grow different tank different history. also i dose lugol's 10 drops per week. to grow zoas u dont need to have youe water too clean.

 

[speargunhunter]

Metal Halide - 14k vs. 20k

<a href=showthread.php?s=&postid=14900705#post14900705 target=_blank>Originally posted</a> by socalmonty
My tank is pretty deep (30") so that's why I am thinking the 14k might do a better job for the corals in the botom half of the tank. Is that a misconception?

my tank is 58x30x30 im using 2x250 DE phoenix 14k for 4x day also 4x54w suplement morning/evening.
i have sps on the top and many zoas on bottom growing like weed in it, sps has decent grow different tank different history. also i dose lugol's 10 drops per week. to grow zoas u dont need to have youe water too clean.

 

[socalmonty]

Okay, so I made the change yesterday and my wife and I looked at it for a couple of hours and decided that everything just looked too washed out. My question is, do corals color up under the 14Ks eventually or is the only benefit that they grow faster? I look at DeMartini's tank, for instance. She runs 14K MH and her corals are beautiful and brilliantly colored. I also run two 110w VHO actinics and it still looks washed out. Will time improve their appearance or is what I see, what I get? For the time being, I've switched back to the 20Ks.

 

[xtm]

<a href=showthread.php?s=&postid=14943677#post14943677 target=_blank>Originally posted</a> by socalmonty
Okay, so I made the change yesterday and my wife and I looked at it for a couple of hours and decided that everything just looked too washed out. My question is, do corals color up under the 14Ks eventually or is the only benefit that they grow faster? I look at DeMartini's tank, for instance. She runs 14K MH and her corals are beautiful and brilliantly colored. I also run two 110w VHO actinics and it still looks washed out. Will time improve their appearance or is what I see, what I get? For the time being, I've switched back to the 20Ks.

What 14K's are you running? NOT all 14K's (and 20K's) are the same. For instance, there is a HUGE color variance between an Iwasaki 14K and Phoenix 14K. In addition, the ballast you're running also affects the bulb's color rendition.

You can be using 10K and still get great, great colors.

Your wife thinks it's washed out because the bulb is new. You need to wait for about a week for it to stabilize. I don't know but it sounds like you're using a Phoenix bulb? If so, then that is another reason. IMO that bulb has got to be the most washed-out bulb I've ever used. Very strong in the 460nm and almost none at the 420nm, creating the washed out look. (some people actually like this)

Here's my 60g cube with Phoenix 14K and Icecap ballast.... yuck

My absolute favorite bulb is the Ushio 20K on Advance M80 ballast. It made every SPS in my tank pop it's ridiculous. The growth is not too bad either.

See the difference? Notice how the 20K is more "daylight" than the 14K?

I see on your gallery that you mostly have softies. I think that a 250-watt setup is more than sufficient. 400-watt is overkill for your setup IMO. Your tank also looks VERY new. You need to wait about a year (yes, a YEAR) to get that "matured coloration" look.

I have to tell you though, there is so much more to growth and coloration than just bulbs. I would say that 80% of SPS keeping relies on strict water parameters than light or flow, in my experience. have fun!

 

[xtm]

<a href=showthread.php?s=&postid=14900241#post14900241 target=_blank>Originally posted</a> by socalmonty
Thanks. I switch my bulbs every six months. My current bulbs are only three months old. My tank parameters are good and pretty stable, I think. SG 1.025, MG 1425, CA 425, Alk 10. I dose four drops of Lugol's twice a week and do a 15g water change every week. But still not much zoa growth. I want a zoa garden but so far it's not happening...

According to various tests (some by Sanjay), most bulbs lose about 30% of their output in the first two months of use, then gradually tapers down to about 5% per month for the rest of the year. Therefore it's not economical to replace your bulbs every six months since they still have plenty of life left. I would say that 12-14 months would be optimal.

I'd be REALLY careful with Lugols, unless you're testing for Iodine. It's very concentrated.

Have you checked your zoanthids for nudibranchs? (That would be the only time Lugols is good for.... for killing nudibranchs). Many many years ago when I kept zoanthids, these nudibranchs wiped out all of my zoas. You should check yours.

There is so many parameters involved. All I can say is read, read, and experiment.

 

[socalmonty]

Thanks so much, xtm. Wow! You have such a beautiful tank. I am running two 400w 20k Helios SE bulbs (recommended by Tat Tropical Illusion in Thousand Oaks) on a Hamilton ballast (I started out with Hamilton 20k bulbs). The 14k bulbs I tried were the Ushios. Maybe I should try them in the 20k. Or maybe I should switch to a fixture with three 250s.

I think I may have some nudis. When I dipped some of my zoas recently, I saw a couple of them wriggling in the dip. But I haven't seen any on the zoas in the tank. I will have to do some research to figure out the best way to deal with them. My tank is so deep that it's tough for me to reach the zoas at the bottom to pick anything off of them and I don't have a quarantine tank. Maybe there are natural nudi predators.

I will also consider laying off the Lugol's. I know what you mean about dosing without testing. Thanks again for all your help.