Reef Lighting Watts per gallon?

[werewolf38]

I read for some corals you need 5-7 per gallon on the average 3-5 is best... then I look at lighting fixture prices and fall out of my chair. I am wondering though can I get away with standard lighting and perhaps one or two 250 watt metal halides in certain areas of my tank where the rock is higher that I would mostly put the corals? The "tank" in mention is a 210 gallon that is not setup yet other than its on the stand and in the location, where I want it. Nothing else in it or on it. I want to try some of the more light intensive corals. But was really wondering if I need to light my entire tank to 7 watts per gallon? Or if I can use just one or two 250 watt metal halides in those areas of rock closer to the top of the tank in addition to the power compacts that already provide 4-5 watts per gallon now?

[Jnicho]

Originally Posted by werewolf38

I read for some corals you need 5-7 per gallon on the average 3-5 is best... then I look at lighting fixture prices and fall out of my chair. I am wondering though can I get away with standard lighting and perhaps one or two 250 watt metal halides in certain areas of my tank where the rock is higher that I would mostly put the corals? The "tank" in mention is a 210 gallon that is not setup yet other than its on the stand and in the location, where I want it. Nothing else in it or on it. I want to try some of the more light intensive corals. But was really wondering if I need to light my entire tank to 7 watts per gallon? Or if I can use just one or two 250 watt metal halides in those areas of rock closer to the top of the tank in addition to the power compacts that already provide 4-5 watts per gallon now?

First of all forget about watts per gallon...that's old info and it really does not apply to the newer types of lighting.

Secondly if you want to keep the "light loving" sp. in a 210G be prepared to shell out some bucks (sorry but lighting is one area of this hobby where you can't skimp much)...What are the dimensions on this tank...MH's are very "narrow" and have very little light spill over...the general rule is one MH for each 2' of tank. I saw a 90 lit with a single MH the other day...I don't think you want to go that route...It was not good on that tank so I think it would be dismal on such a big tank. There are some reflectors that "spread" a little more but then you loose light penetration and I'm guessing this is a pretty deep tank.

[werewolf38]

Dimensions are 84" long, 24" wide and 24" high

[mg]

You could get away with 3 250W MH and be able to keep anything you want. The 250W is a good choice for a 24" tall tank if you want to keep SPS or calms. You could use a slightly bluer bulb (14K) and not have any additional actinic lighting as well.

Does the tank have a conopy and if so what are the dimensions of that (really just looking for height)

[know-it-all]

agreed, throw the watts per gallon out

[werewolf38]

No tank canopy at all and no plans to add one anytime soon.

[mg]

Originally Posted by werewolf38

No tank canopy at all and no plans to add one anytime soon.

So you need some kind of fixture or pendents for a finished open top look, no retrofits.

What type of bracing is there on the top of the tank? 2 braces equally spaced? 1 brace? eurobraced?

[OneDummHikk]

Originally Posted by werewolf38

I read for some corals you need 5-7 per gallon on the average 3-5 is best...

You can totally forget the "watts per gallon" rule. As said, it is old. But, it only takes thinking about it to realize why it is wrong. My 125 is 6 feet long and 17" tall. A 120 Tall is 25" tall. And a 120 cube is 31" tall. All three tanks are basically the same volume but the lights for one setup won't even be close to adequate for another one. The height of the tank, the clarity (clean ness) of the water, and the substrate will all affect the light you need. Length of the tank tells you how many MH or how long a T5 you will need, and the depth (front to back) will also play a part in how many you need.

The key is how much of the light reaches the bottom of the tank.

[Elegance Coral]

Originally Posted by werewolf38

I read for some corals you need 5-7 per gallon on the average 3-5 is best... then I look at lighting fixture prices and fall out of my chair. I am wondering though can I get away with standard lighting and perhaps one or two 250 watt metal halides in certain areas of my tank where the rock is higher that I would mostly put the corals? The "tank" in mention is a 210 gallon that is not setup yet other than its on the stand and in the location, where I want it. Nothing else in it or on it. I want to try some of the more light intensive corals. But was really wondering if I need to light my entire tank to 7 watts per gallon? Or if I can use just one or two 250 watt metal halides in those areas of rock closer to the top of the tank in addition to the power compacts that already provide 4-5 watts per gallon now?

Your idea will work fine. If you have 2 top braces on the tank you can put one MH in the center and the light demanding corals under it. If you want to expand later you can always add MH's on the ends. The only thing that matters with light, is how much reaches the animals you are trying to keep, and the quality of the light itself.

[werewolf38]

To answer the bracing question there are two braces dividing the tank into 3 sections. Very odd size tank, I bought it from my local pet store that was going out of business and he had it as his show tank for many years.. tank and everything other than the rock and fish was $700!! I know it is fully functional as I saw it setup there for years and even right before he took it down. The lighting he was using was all power compact and he had mostly polyps in and some fish and live rock but none of the hard corals or anything too complex. He didn't even sell any corals that I remember.

[OneDummHikk]

Originally Posted by werewolf38

To answer the bracing question there are two braces dividing the tank into 3 sections. Very odd size tank, I bought it from my local pet store that was going out of business and he had it as his show tank for many years..

That is the same way my 125 is. It has two braces instead of one. If he had it set up with PC's, then use PC's if you have them.

[Jnicho]

Originally Posted by OneDummHikk

That is the same way my 125 is. It has two braces instead of one. If he had it set up with PC's, then use PC's if you have them.

You don't want to add SPS corals, nems or clams to a tank for at least 6 months (a year is even better if you are not experienced with them). So yea, if you have the PC's start with them...once you have it established an flourishing with hardier corals you can upgrade the lights.