Lighting a 225G, 30" high reef tank

[Tullsterx]

I'm making plans for lighting a 225G, 30" high tank.

I'm think about mounting a 72" 2-160W VHO light fixture and 3 DIY 400W Metal Halide lamps within a DIY hood. (1520 W - 6.7W per gallon)

1) Would this be enough lighting for a 30" deep tank?

2) How high should the MH lamps be mounted above the water?

3) What's the best way to ventilate the hood? Is there a "best" place to put the fans?

4) Should the top of the tank, under the hood, be covered, with glass? Or not? Or covered with something else?

Thanks

 

[austinsdad]

#4 - I think with thay much light, you're gonna need to leave the top bare in order to dissipate (sp?) that heat. Just the hood and retro-fit lights - with fans, of course.

For Q #1, what kinda coral are you targeting? I'm only using 3x150 MH and 4x96 PCs and see water temp swings upwards of about 3 degrees a day without fans. When I run 2 fans into the hood, it's a lot better. I put the 2 fans on timers to come on and off with the MH lights.

I was confused on question #2 if the lights will be in a hood. The height will be determined for you, right?

 

[revhtree]

Another question:

How long is the tank?

 

[Tullsterx]

The tank is 6 ft long. It's a 72"x24"x30".

And I'm building the hood, so, I will have some flexibility in how I mount the MH lights. Or I could leave the top off the hood and suspend the lights from the ceiling.

I thought that I needed the 400W MH because of the depth of the tank. I don't want to have to worry about making sure everything stays on a shelf of rock or anything. But, I plan on having plenty of rock.

But, am I likely to have MAJOR heating problems with the 400W?

Oh, and I'm not sure about what corals. I'm planning on adding some reef-safe fish, green chromis, 2-3 Tangs, Building up my live rock collection and then upgrading the lights eventually and probably add an anemone and start looking at what corals might work.

 

[austinsdad]

If you can decide that you're not doing hard corals that are high light needy, I think you could get away with a lot less light. Sounds also like yu're talking about having a lot of rock to place your corals on. As you place the corals further away from the bottom on those rocks, the tank isn't so deep all of a sudden. Low light corals can do fine on or near the substrate. Medium users above the substrate to the middle, and those hihg light users from the middle to the top.

And yes, with hooded lights and as much light as in your current plan, I believe you will have temperature issues. Remeber I'm getting that 3 degree swing with my lights. But if the MHs go above the hood it should do much better than having that heat contained within a hood. Not sure how the shadows will work with that setup - lights shining down with a hood (and I presume with openings, of course) below it.

You can check out the height of my hood below to maybe give you a better idea what I'm experiencing.

While you're thinking about lights, you should check out Eric Borneman's "Aquarium Corals" book to help you decide on what you may wanna have and support with your light decision.

 

[Tullsterx]

Hey, great idea on the book.

Thanks!

 

[abnmojo]

From my experience, MH that hot should be close to a foot from the surface of the water. I have a 8" tall, 48"long wooden hood, open in the back for airflow, and my 4 X PC and 2 X T5 will heat the water a lot. I have to keep the temp below 70 in my basement or my tank temp creeps over 80. I had to remove the glass from the top of the tank to keep the temp down. I have a lot of pumps in the sump so I know that heat is an issue as well, and something else for you to think about.

From the DIY tanks I have seen, the higher the hood the better for the airflow and heat dissipation, and fans are a must. For this reason, I really like the pendant MH lights if you can find a way to make them work for you. You really don't want to spend all the money on this and find out later that you also are going to need a chiller as well. You know how much it is going to cost to chill a 225?

 

[angelscrx]

A couple of ventilation options for you.

1. Clip on fans on both sides of the hood. 6" from Wal-Mart work great.

2. Hood fans (ebay) with vent ports cut out on the sides of the hood. Fans on one side and holes on the other. Fans would inserted into holes cut out for them.

3. Since heat rises you can also places fans on the lid of the hood to draw the heat up and out of the hood with vent holes on the sides.

No matter what you decide keep the back of the hood open.

How deep is the tank from front to back? I have a six foot tank and it's 32" tall by 18" front to back. I light mine with 3 250W MHs 6 inches from the top of the water with NO florecents (upgrading them to VHOs in the future) and my SPS do fine.