Lighting set up questions for 2 X400 watt MH setup for 50G t

[Jacob1]

I have a 50 G breeder 36x18x18 and have a dual 400w MH ballast. I have one of the ballasts hooked up to a Iwakasi 6500k bulb. I would like the look of actinic's but would prefer not to use the florescent tubes. Could I just hook up a 10k bulb or a bluer bulb in MH form to get the cool florescence caused by actinic lighting?

Also any lighting suggestions for setup of the MH. I was thinking either two Iwakasi (If I do break down and get actinic supplemental lighting)both slightly off center of the tank and put them on overlapping time schedules. Thought this might help imitate the sun best - with greatest intensity at noon but also light source gradually changing position over the corals leading to a more natural growth pattern. Either that or putting two MH bulbs very close and having one of them be a very high K bulb to bring about that actinic look.


I will be using this tank to raise aptasia anemonies for my prized Bergehia slugs.

just kidding - hoping to set up a sps, lps and clam tank. Will be using a T.F. multi for filtration as well as a 20 Gallon refugium/algae scrubber for nutrient export. Hope to get a Ca reactor once I start adding corals.

 

[Len]

Jacob,

This is going to be one BRIGHT tank. Unfortunately, it's also going to be one hot tank. Unless the tank is located in a very cool place (sub 60 year round), or unless you have a chiller, you're going to have heat issues. The volume of water simply can't buffer temperature.

As for flouresencing: only true actinics produces this effect. No MH that I've used (10K, 12K, 20K, German/Euro/American) does it. The higher Kelvin bulbs look more blue, but not in the same manner as actinics.

 

[Jacob1]

I was thinking of two muffins blowing into an open back canopy. It will have a 10 gallon sump and a 20 gallon high refugium with 2 64 watt LOA fixtures and a muffin fan in the canopy. Both canopy's will be 10 inches high. The MH will be mounted about 3/4" off the top of the canopy So the bottom of the bulb will be aproximately 6 inches above the water.
With a better knowledge of the setup do you still see heat being a major issue?

 

[Len]

Jacob,

I can only venture a guess that heat is still a concern you have to monitor and control. On my 120g, 2 400 watters + 440 watts of VHO (cooled by 3 4" fans) and 2 inline pumps causes it to reach high eighties if unregulated. My MH's are 10+ inches above the water line. Of course, I'm in warm southern cali. Just monitor the temp.

 

[McReef1]

Doesn't anyone else think that Jacob will be battling algae problems incessantly with 16 watts per gallon of lighting? Forget about the heat generated...

 

[Len]

Algae growth is more a function of nutrient levels then light availability. If nutrients are controlled, no amount of light will promote algae growth.

Low light levels promote cyanobacteria growth in my tank. Interesting thing about cyano is that celluar O2 is actually toxic to it, but it's evolved export oxygen (product of photosynthesis) from its cells. Given this, there's a good anecdotal correlation that high light should actually impede cyanobacteria growth.

 

[Keith wants a Reef]

I have a 55 with 2 400's, if you run them both you'll boil the water. What I did for mine (no expert), was to totally open the back of my hood (self made) and I have a 6 inch fan blowing continously right below the bulbs pointed towards the back of the open canopy. Another downside is your going to suffer some serious evaporation. Good luck

 

[Anonymous]

I have a 55 and I thought I was going overkill with 2 250. 2 400 you r fish are going to be boiled. However served with lemon and a white wine...... All kidding aside I think that is a bit much. Would be replicating the sun on say, Jupiter, but not here.

 

[Greg Hiller]

>Low light levels promote cyanobacteria growth in my tank. Interesting thing about cyano is that celluar O2 is actually toxic to it, but it's evolved export oxygen (product of photosynthesis) from its cells. Given this, there's a good anecdotal correlation that high light should actually impede cyanobacteria growth.<

I have a funky green cyano that grows 5 inches away from a 400 W Iwasaki!

Jacob's question:

>What do you thnk of 1 400watt Iwakasi 6500K in a open back canopy with two
>muffin fans? Would I need actinic supplementation?<

There are lots of different ways to light a reef tank. Seems to me if you have a pair of 400 watters you should get yourself a bigger tank. Used tanks are very inexpensive, FWIW.
Yes, you can raise the lights off the water for less heating, but this will also mean less light into the tank. So, if you want to light efficiently (and heat, inefficiently) your house this is one way to do it.

I personally feel that the best way to efficiently light a tank is to use one 250 W bulb per 2 ft of tank length, with VHO supplementation. If the tank is deeper than usual, or you really plan on having a lot of SPS that you know need bright light, then use 400 Watters, or use a single 400 Watter in the center of the tank for that extra boost. I can tell you that a 400 W Iwasaki by itself does not (IMO) provide a nicely balanced light color for a display tank. I use a single 400 Watter on my frag tank, but I don't care what the frag tank looks like. You really need some actinic VHO to get the coral colors to come out.

> What I was also thinking of was set up the two bulbs
>slightly off center and have there photo period overlap by 4 hours to
>simulate the greator intensity at midday and the passing over of the sun to
>stimulate more natural SPS growth.<

That's not a bad idea.

What do you think? Also what do you
>have for lighting over your display tank. Any specific K values you feel
>are benificial or do you go for PAR?<

I think it depends largely on the coral, but you need decent PAR for any considerable growth.
>
>Seems like a waste of one of the ballests not to use it. But I guess I can
>always use it in the future when I upgrade and in the meantime save on
>lighting costs.

Unfortunately, a single point source of light is not a good way to light a tank. Some corals will grow toward the source, and form unnatural, and IMO ugly growth forms.

 

[Luminary]

I don't think it's quite as unrealistic as people may think.

I am running the same tank with a little less lighting. I've got 2 250 12000K Sunbursts over the tank. I also have a 10 gallon tank running a 175W 10000K Ushio that is plumbed into the same water source. My canopy has about a 5" openning running lengthwise across the back of the tank. There are 2 4" radioshack fans, one blowing in and one out. The 10 gallon is completely enclosed with a 4" hole (for a fan that was unnecessary). I mention the 10 gallon, because it heats the water, but does nothing to cool it.

The bulbs are about 7" from the water.

The hottest the tank gets is 83 deg. That is in the middle of the afternoon with the florida summer sun shinning directly on the tank. During the winter months when there is no direct sun I need a heater to keep it around 80.

The 400 6500K bulbs are going to add more heat than the 250 12000K bulbs that I'm using, so you will probably need more cooling than I do.

Also realize that you will probably have some serious evap. I top off 2-2.5 gallons per day.

There is alot of discussion about which bulbs to use, but if you are looking to get the blue color, you may want to look into the 10000K or 12000K bulbs. I very happy with my 12000Ks. It's a nice blue tint without the need for supplements. I would like it a tad bit brighter (the 175 10000K looks a little brighter), but it's sufficient for anything I want to keep. I hate the look of just the 6500Ks, and didn't really have room in the canopy for supplementals, so I went with the higher temp bulbs.

If you want some pics of how my canopy is setup:
http://www.liquidchaos.net/Galleries/50Gallon/Setup/index.htm

Sorry this was a bit long, but hope it helps.

[ July 11, 2001: Message edited by: Luminary ]