Dusk/Dawn...Do you do it? (Using VHO's,etc..)

[SaltyNewb]

All I have on my 29g now is a Giesemann 150watt Nova II, but was planning on running two 24" VHO's for the dusk/dawn effect?

Do you think it matters or is it just for show? I don't know about running my halide only for 10-12 hours?

I guess if you have the VHO's then I could use a 13k bulb with super actinic VHO's, instead of just having a 20k halide?

[Putawaywet]

I'm a believer. I added 13w PC's specifically for this purpose. So my photoperiod starts with a pair of 13w PC's for an hour, followed by 4x 54w T5's for another hour, and then 1 250w MH follwed by a 2nd 250w MH 30 minutes later. 10 hours after the last MH comes on the process begins reversing itself.

Brett

[eng94]

i think it is nice to see a dawn and dusk i put two vho's on one before and one hour after my halides

[donfishy76]

I think it is nice to look at, like for us, the watchers, but the corals have no affect either way. I dont think it is that important.

[optimus prime]

^ I could not dissagree more. Of course it has an effect on corals. More light, more spectrum, more growth, and more color. IME true actinic 03 ( not pc bulbs) also helps promote corraline. Now i cant say for sure but i would think a gradual increase in light would be better that a full blast all at once meaning it would be less of a shock going from dark to actinic to halide then from darkness to halide (full sun). It is more natural so i dont see why it would not help.

[dcoufal]

Originally posted by optimus prime
^ I could not dissagree more. Of course it has an effect on corals. More light, more spectrum, more growth, and more color.

Full agreement here....

384W Actinic (420 & 460nm) - 11am - 9pm
450W HQI 14k MH - 1pm - 7pm
4W Moon - 9pm - 11pm

Dwain

[scottfarcuz]

I ran mine with a dusk/dawn setup and later switched to just MH's. I guess its neat for viewing purpose but the corals don't seem to mind either way.

I have seen more than a few frag/growout tanks in my time and none of them used any dusk/dawn lighting. More light is not always better. There is a thread in the SPS keepers section with some users running as little as 3 or 4 hour photo period with beautiful tanks.

[tekknoschtev]

We have 2x 95W VHO .03 Actinic bulbs that turn on 1.5 hours before the halides and 1.5 hours after the halides go off. I cant say whether or not that I have seen any difference in the corals, however, for viewing it is very aestetically pleasing.

As for the dusk/dawn not affecting corals? Tell that to the people that buy a moon phase controller for their moon lights, and have their normal lights adjust to replicate different photoperiods depending on the day of the year. I personally have no experience or any data to back up any claims I make, however, I can say this, that if I was awaken to 800W of metal halide lighting 24" from my head, I'd be more than a little POed. I like to gradually wake up, not wake up in a tanning bed :p

As far as frag/grow out tanks go, we have ours with our old 2x 96W PC 50/50 fixture. Everything is still on the same timer as the reef before we upgraded, so our corals get a good amount of dusk/dawn. I think it looks cool because I can see what they look like under the actinics. Once we need to replace the actinic, we're probably going to get a second 10K bulb though, just to give that added edge to the weak PC fixture.

[sevise]

I did dusk dawn because I noticed the fish used to freak when the MHs would suddenly go out.

2x54W T5...1/2 hour wait
2x54W T5...1/2 hour wait
250W MH...1 hour wait
250W MH...8 hours then the reverse

After I did dusk/dawn I noticed the corals would be fully opened by the time the MH would come on. In the evening the fish will get quite calm and 'bed' down when only the last T5s are on. If it reduces stress on them its worth it.

[donfishy76]

Originally posted by optimus prime
^ I could not dissagree more.

I was simply going by what I read in a reef book. On the other hand, i do totally agree that acinic light spectrum throoughly helps in the growth of coralline algae.

[orlenz]

I run 10k Halides , So I use actinic VHO's for dusk / dawn effect, and moolights at night , I try to keep it somewhat natural for the inhabitants.

[tekknoschtev]

Originally posted by orlenz
I run 10k Halides , So I use actinic VHO's for dusk / dawn effect, and moolights at night , I try to keep it somewhat natural for the inhabitants.

And keeping on that "natural" approach, when I trip the circuit breaker with the vacuum, its a cloudy day :p

[MIKE NY]

I run 10k Halides , So I use actinic VHO's for dusk / dawn effect
ditto except I use PCs........

[donfishy76]

Ok, to all who are worried, and think it is good, read Calfo's prop book, page 142. Granted it is his opinion, but he thinks it is no big deal whether or not corals get a dawn/dusk effect from our lights.

[donfishy76]

Sorry, top of page 143 says "Some aquarists opt to run such bulbs (actinics) for an hour longer before and after metal halide cycles. I do not believe captive corals benefit much or at all from the attempted waxing and waning of artificial lighting."

just the reasoning behind my original statement.

[Entropy]

I think the dusk to dawn is more for the fish than corals. Corals could care less IMO. The problem is that VHO's are not really much better than halides IMO. Actually they are not even as good, because at least the halides come on gradually over 30 seconds or so. My VHO's pop right on, and pop right off. I guess there is less light, so the effect is not as pronounced, but if you really wanted to do dusk/dawn you would probably want to have some kind of dimmable light setup start and end the day.

[swashbuckler]

we really dont have enough data yet to justify whether or not dawn/dusk is needed, just like how we dont have enough research to determine whether dosing various trace elements are needed. the only approach we can take is to try to replicate nature as much as humanly possible, as the discovery of LR and natural means of filtration have had profound effects on the hobby.

Like mentioned by entropy, my VHO's also POP right on... not very natural if you ask me, but does it effect the corals? couldnt tell you for sure. but it would be a wise goal for slowly increasing light, as it may have some unforseen long term effect that we may not know. As in nature, light levels change drastically in the course of the tropic day.. overpassing clouds to overpassing schools of fish, sometimes staying in clusters for very long periods of time blocking the light to animals below.

just my nickel :D

[SaltyNewb]

you could always get one of those dimmers for the ice cap ballast, but they are near $200

[mikebon111]

optimus prime
^ I could not dissagree more. Of course it has an effect on corals. More light, more spectrum, more growth, and more color.
I'm with you on that.
IME true actinic 03 ( not pc bulbs) also helps promote corraline
Not with you on that
I put tru actinic 03 PC's over my tank and corraline grew like crazy. Whats wrong with PC's?

[timespinner]

I run my VHO bulbs for about 12 hours, and my two MHs for about 5 hours. I have the lighting on timers so that one MH comes on about 20 minutes before the other. IMO - I prefer the look of the tank when only the VHOs are on or when there is only a single halide and the VHOs on. My feeling is that this really don't have that much effect on coral growth.

[elephen]

It definatly adds a nice touch. 9AM VHO's on, 11AM halide on, 11:30AM halide on, 6PM halide off, 6:30PM halide off, 10PM VHO's off.

Nice :)