Degrees K

[hamdogg08]

I'm confused about lighting for the reef tank. I already have a 6700K bulb, and it seems like I could use that bulb for corals that live closer to the surface. If this is so, where does the actinic lighting come in to play? Could someone tell me what "entry level" corals would thrive in a 10 gal with a 96 watt 6700K CF bulb?

[hypertech]

In my 29 I have xenia, zoos, rics, shrooms, acan lord, favia all doing well under 144W PC and they did fine before I upgraded and had 72W.

I think the orange monti is doing well and the jury is out on the pocci. Its turning a little brown on the bottom but I think it may have fallen on the acan so I don't know if its the light or something else.

2 of 4 SPS frags I got seem to be doing well. The other 2 really have never extended their polyps so I'm not holding my breath on them.

I'm upgrading my flow to 660gph hoping that might help the pocci because it is very cool.

I have 1 10K, 1 Actinic and 2 50/50 bulbs.

I'm not an expert by any means, but I'm guessing softys and LPS would be fine.

[hamdogg08]

Did you have a 6700 or 10,000K bulb on the tank?

[hypertech]

Sorry - you must have posted when I edited to add that

1 10k
1 Actinic
2 50/50 10k Actinic

[hamdogg08]

If I can only have one bulb, could I get by with the old 6700, or am I going to need the 50/50?

[Goldpony75]

i think when it comes to pc that the color temp is more a personal visual preference. its not going to affect coral growth much either way you go(except for going only actinic). the lower the k value(6700k) the more yellow you see the higher the k(10,000K) the more blue. i may be wrong and if i am someone will chime in a correct me.

[hamdogg08]

Are the actinics super important? I don't really understand the difference/contributions.

[hamdogg08]

OK, I just found the answer to the question. The higher deg K, the easier it is for the corals to absorb the light. The actinic lights seem to be like a supplement for the corals' light needs when using anything under 10,000K bulbs.

[hypertech]

The actinics also help with the color. I think it is too white to have 10ks without any actnics on. The 50/50 has a nice color to it.

Some things kinda glow under actinics too. I have no idea why that is.

[spsick]

2 of 4 SPS frags I got seem to be doing well. The other 2 really have never extended their polyps so I'm not holding my breath on them.


if you're talking about the ones you got from me, can't remember which ones I gave you, but some of them only show polyps at night. so you know.

[hypertech]

if you're talking about the ones you got from me, can't remember which ones I gave you, but some of them only show polyps at night. so you know.

Yes they are the ones I got from you.

I tried sneaking up on them at night. Two are looking really good especially the one with the green polyps. One is still all colored but I never see PE. The other seems like a lost cause. Its bleaching and I never see PE. Maybe the pump upgrade will help I'm going from about 10x to 25x turnover.

I wonder if I just don't have enough light for the two?

[David Grigor]

with just a 6500k bulb your not going to get much flouresce from the corals so they are going to look pretty blah. Not going to make for a aethetically pleasing tank.

Corals will do fine though.

You likely going to want a 50/50 bulb when time to replace.

Lastly, algae really like the lower K which is why it is more prefered for refugiums and the like. So if you water quality is not ideal, you may promote more algae than a higher K bulb would so keep a close eye on your water parameters and do everything possible to keep nitrates and phosphates low ( which you should always strive for ).