Lighting

[truck0000]

I have a 75 gal. Oceanic tank. I have a 260 watt and a 220 watt pc fixture on it. Thats a total of 480 watts of light. I was wondering if thats enough light for a corcea (sp?)clam,zoos, and maybe some sofites?

[akm]

The zoos and softies would do alright but you might be asking too much of the clam since they are one of the higher light needing clams.

[duc]

I am no expert but "I think" the equation is 5w per gallon so I would say yes. I have everything you listed under less light with no problems including the clam.
Clif

[pilot_bell777]

From what I've read and heard from others that know light it is not teh added watts that matter as much as the intensity. So 2 x 250watts wouldn't be as good over a deep tank as 1 400watt because the 400 reaches deaper in the tank than the 250s even though their combined light is 500watts.

So depends on the depth of the tank and were you place the clam I guess to get an acurate answer.

[matt]

The "watts per gallon" equation is kind of useless. What you need to know is the light intensity, usually expressed in PAR (photosynthetic available radiation) or PPFD (photosynthetic photon flux density) Man, I could be really screwing up those terms, but it's something like that. The point is, there is a way to measure the amount of light energy that is useful to photosynthesis, and those 2 terms are the ones currently used. The watt is simply a measure of how much power it takes to run the light.

Metal halide lamps have much greater intensity than do power compact bulbs, and provide light that is much more useful for photosynthesis. Since the clam you're talking about typically lives at shallow depths where the sunlight intensity is far beyond anything we would produce in our tanks, it needs as much light as you can practically provide for it. This means mh lighting. A couple of 10k 250W bulbs over a 75 gallon would work fine. 10k refers to the color of the bulb in terms of degrees kelvin. The higher, the bluer, generally speaking. It's a little misleading; it's 10000 degrees kelvin, but noone says 10k k.

Anyhow, something tells me if you stick around MAAST this winter you might have a great chance to learn all about aquarium lighting from someone who REALLY knows his stuff.

[GaryP]

You're better off calculating watts per square foot. So, a 4' X 1.5' is 6 sq. feet.

Crocea and maxima clams and SPS require around 100 watts/square foot. Figure a little over 60 watts/sq. ft. for soft corals, squamosa and derasa clams. So for your 75, you need at least 360 or 600 watts. I have 440 watts on my 75 gal. softy tank.

If your tank is over 24" deep, multiply these numbers by 1.5. Of course, as Matt pointed out there is another factor to consider. PAR is a big factor. A 20K MH bulb has half the PAR that a 10K bulb does. So all watts are not equal.

[Richard]

I think you'll be fine with that lighting. You should pm Andrew and get his thoughts as far as wattage and bulb types. He's been keeping crocea's, maximas and sps under pc's for a long time.

[cpreefguy]

As far as clams go, you would be alright with a derasa. You could keep some corals, they might not display the colors/growth you are hoping for though. My $.02 is to decide what you would ideally like to keep, whether it be SPS, LPS, Softies, Clams, whatever, and make your lighting decision based on that. If I can tell you one thing (based upon experience) is that when people buy lighting, they are eager and buy whatever they can get at the time, and end up wasting money because they end up upgrading later on anyway. So I say think about it, save your money, and get what you want.

[matt]

I really think you should forget about using watts as a measure of light effectiveness, especially if you're trying to compare MH lighting with PC. Plus, not to disagree with Gary too much, but surface square footage give you no information about tank depth which is a big factor in determining appropriate light for specific animals.

A light's wattage only refers to how much electricity it takes to operate, and gives you no direct information about light energy useful for photosynthesis.

[hobogato]

i ran power compact lights for year, up to 7 watts per gallon, and never got the color and growth i have seen in the last 8 months of running metal halide with PC actinic suppliment. like CP said, you can go with PC now, but more than likely you will eventually want to upgrade.

[truck0000]

Thanks for the replies. I plan on upgrading next year when I get my income tax. Was just trying to make sure that I wouldnt kill anything b/c of lack of light. I geuss i get some zoos and see hom they do to start.

[matt]

Rob;

Another thing to consider, and this is what really put me onto MH lighting, is that it looks MUCH better IMO than florescent lighting. It's a point source, like the sun, and so you get much more realistic shadows and rippling effect. I went to the beach one sunny day in CA while on a business trip, looked at the way the sunlight interacted with the water, and shortly after ordered MH light for my tank.

[bprewit]

MH lighting does not have to cost a arm and leg to get. Cutom lights with VHO and MH are pricey but if you are the least bit handy or have a friend that is you can get say a raw coil and core 250W MH ballast for around $45-$50 at local electical suppliers, $30 for a reflector and socket from hellolights and another $65+ for a 250W bulb. 175W are a bit less expensive and 400W a bit more but dont let custom lighting prices scare you away from MH lighting as anyone with basic electical knowlege can wire these up safely and you or someone on here can build a nice hood or retrofit your existing hood. I spent way too much money upgrading lighting until I finally realized it didnt need to be that expensive or difficult. Just figured would mention this to ya

[cpreefguy]

Check ebay, you can get KILLER deals on brand new lighting.

[hobogato]

hellolights had an ARO magnetic ballast retrokit with reflector and mogul socket for $129 not to long ago. found some XM 250w 15kk bulbs on ebay for $64 with free shipping.