Lighting 101 for a newbie

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Pat - 20 Apr 2006 16:45 GMT

I am in the process of making plans to construct a lighting fixture to
facilitate the conversion of my FOWLR tank to a Reef tank. I have the
resources of many people very knowledgeable about lighting and
electricity so I'm not going to zap myself or my aquatic friends. My
problem is that I have no immediate friends that know anything about
lighting and creatures of the sea. I have a 75 gallon tank. According
to some reasearch I've done(which is strewn with conflicting opinions) I
think can get by with 2 175W 10,000K MH bulbs with a mogul base. 2
175W MH Ballasts. 2 sockets for said bulbs. reflectors. And a box for
it all.

I am looking to keep a clam or 2. An anemone. And a few assorted corals.

Questions that I still need answered.

1. I have an assumption that I'll need to enclose the MH bulbs in a
metal box with a glass bottom to protect the bulb from ever getting wet
and because of the high temp. Is that a correct assumption? I'm a
little concerned about the glass getting too hot and shattering also.
Again not sure what kind of heat I'm looking at.

2. I plan on putting it all in a wooden canopy. I can install fans in
the canopy or in the individual boxes to aid in heat disbursement. Not
sure how much heat I'm looking at. Just trying to plan ahead.

3. Is this a good light config for what I'm looking at or am I way off
base? (I also plan to try to work some LED's in there for moon lights.)

4. For not all that much more money I could get a 2 X 250 Watt setup.
But that introduces more heat and will suck more power. Is that
something I should do...or will the 175's be just fine?

5. Knowing nothing about corals(that's the next part of research). What
impact do they have on the bioload of the tank. I know the theoretical
"rules" of fish per gallon. But I assume that adding corals anemones
and clams will reduce the number of fish I'm allowed to have. But I
cannot find any information on what effect they have on the total picture.

Sorry for asking so much. Any help is much appreciated. I always try
to get a complete understanding before embarking on such adventures.

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Don Geddis - 21 Apr 2006 17:03 GMT

Pat <ozman213@hotmail.com> wrote on Thu, 20 Apr 2006:

> I am looking to keep a clam or 2. An anemone. And a few assorted corals.

All requiring intense lighting. (Some corals don't, but hard/stony corals do.)

> 4. For not all that much more money I could get a 2 X 250 Watt setup. But
> that introduces more heat and will suck more power. Is that something I
> should do...or will the 175's be just fine?

The general rule of thumb for reef tanks is, the more light the better.
If you're deciding between 2x175 vs. 2x250, you should almost certainly
choose the 250W bulbs. Natural sunlight is far more intense than pretty
much anything we generate in the home. (Hard) corals (and clams and many
anemones) will grow faster and brighter with higher-watt lights.

> 5. Knowing nothing about corals(that's the next part of research). What
> impact do they have on the bioload of the tank. I know the theoretical
> "rules" of fish per gallon. But I assume that adding corals anemones and
> clams will reduce the number of fish I'm allowed to have. But I cannot find
> any information on what effect they have on the total picture.

No effect, at least in the way you're thinking.

The problem with fish is that, as they process food, they naturally produce
ammonia waste -- which is unfortunately highly toxic to themselves. So you
need to do something about that huge amount of ammonia, and the limits of your
ammonia processing (whether mechanical or biological) give you the "bioload"
capacity of your tank.

But corals, clams, and (to some extent) anemones don't really produce ammonia
waste in the same way. You can pack those things as densely as you want in a
reef tank, and it won't affect the water quality. (In fact, it can often
improve water quality a little, as most of these kinds of animals are filter
feeders, and constantly extract microscopic life from the water column.)

There are two caveats:

1. While corals don't pollute the water just by living, the way fish do, it
is true that nearby corals of different species can engage in chemical warfare
with each other. This is too complex a topic to say much more right here, but
it's possible that you'll get fouling of the water over time by placing
aggressive corals near each other, and having them deliberately generate toxins
(and releasing them into the water) in an attempt to kill the competitors.

2. (Stony) corals, clams, and anemones tend to require higher-quality water
conditions than fish. Fish are the ones that produce the ammonia, but they
can also tolerate more water toxins (ammonia, nitrates, etc.) than more
invertebrates. So, you may have an existing tank and a bioload that seems to
be "working" today, but from a reef perspective it is possible that it is
already overstocked with fish. Mostly depends what your chemical measurements
show for the nitrogen cycle.

That said, if your tank is currently functioning with excellent water
conditions, adding corals & clams will have no real impact on the "bioload
capacity" of the tank.

-- Don
_______________________________________________________________________________
Don Geddis don@geddis.org http://reef.geddis.org/
If you try to fail, and you succeed, which have you done?

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Pat - 21 Apr 2006 18:03 GMT

Thanks very much for the input Don, appreciated!

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miskairal - 21 Apr 2006 22:24 GMT

Thanks Don, that was very informative without being too technical.

> Pat <ozman213@hotmail.com> wrote on Thu, 20 Apr 2006:
>
[quoted text clipped - 57 lines]
> Don Geddis don@geddis.org http://reef.geddis.org/
> If you try to fail, and you succeed, which have you done?

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Pet Forum / Aquaria / Marine Reef / April 2006

Lighting 101 for a newbie