How much light is needed to have polyps or corals in a salt water fish tank?

Question

I'm thinking of buying a new light fixture for my 20 gallon long fish tank. I would like to get polyps and corals, but I heard they need very high lighting. The fixture is 60 watts, so it's 3 watts per gallon in my tank. I heard in some places that 3 watts per gallon is fine, and in other places they strongly disagree. I would really like it if someone has had a tank with 3 watts per gallon with corals or polyps would respond to this question. If possible, i would like to know what other inverts I would or wouldn't be able to get with my fixture. Thanks.

Answer 1

Before you rush out and buy all kinds of suff, figure out what kind of coral you want. Corals vary with lighting requirements. Some can survive well with normal lighting while others need UV lighting. Drop the watts per gallon stuff. It doesn't work. Tall tanks vs. short long tanks of the same size do not get the same lighting from top to bottom therefore cannot have the same wattage per gallon. I have corals and pollyps in one of my 30 gals with no special light but what it came with more than 30 years ago and they are doing fine. However, the corals and anemone that are in that tank are not particulars on light.

To try to tell you what to get and not to get is difficult since you don't know what kind of coral you want to get. You either have to build around your fish, around your corals or your inverts. I am going to assume you have fish. Build around them since some fish eat certain corals. This is the same with inverts. What fish do you have? Do you have an idea of what coral you would like to have? you may want to research your coral vs. lighting requirements for that type. Make sure they are compatable with your fish. Usually they will list the corals which are compatable as well as with friendly fish.

As far as your fixture goes, that depends on the fixture. They now sell bulbs which mimic certain lighting. Your local fish store should have them in stock. Again, you have to start with your fish.
Good luck.

Answer 2

To keep corals, anemones, or clams you'll need higher wattage than the average fluorescens will produce. When I first started out, I even tried using two fixtures on a tank, without success.

I'm now using a dual tube high output compact fluorescent (3 of these, each on a different tank). One of these fixtures (produces 130 watts of light) is what I use on my 20 long. This is still low for some of the high intensity hard corals and clams, but I'm mainly interested in soft corals, mushrooms, and anemones, so this works for what I have in the tank. Depending on the types of corals you want to keep, 4-6 watts per gallon would be a better amount.

Because your tank is shallow, a compact fluorescent would work a little better than a metal halide (the most intense light - also a big heat-producer!).

Here are some of the types available - I have the Coralife Lunar Aqualight on the second page:
http://www.thatpetplace.com/pet/product/categoryInfo.web?options.passInCategoryKey=22943
http://www.peteducation.com/category_summary.cfm?cls=16&cat=1789

Answer 3

it all depends on what kind you get