How would I build a light like this?

6*54 is way too much light for a 75g. I think that 4 would be already high light. You would have algae problems if you do the 6*54w.

That's all I could comment on. Good luck with your lighting

Assuming you use light kits as good as TEK lights, 6 54 watt T5HO would be very high intensity for that tank. Half of that would be high light. I see that you probably expected that, so you were going to put 3 bulbs per timer. I think I would use 3 bulbs, 2 on one timer and one on another timer. Then you can run one, two or three bulbs, giving you lots of options.

If you really do want that many lights, make the fixture a hanging fixture, so you can raise it enough to reduce the intensity, get great uniformity of intensity, and be able to get just about any intensity you want. http://www.reefgeek.com/lighting/T5_Fluorescent/ is one place to get retrofit kits.

I just don't get how
2 54w bulbs =1.44wpg [which I was told was very low light]
but 3 54w bulbs = 2.16 would be high light

So could I do 4 bulbs and one moonlight. And hang it over the tank and still get high light?

Shadow said:

I just don't get how
2 54w bulbs =1.44wpg [which I was told was very low light]
but 3 54w bulbs = 2.16 would be high light

So could I do 4 bulbs and one moonlight. And hang it over the tank and still get high light?

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that's 2*54w for a T12 type of light. This is T5 and it has way more light intensity than any other kind of fluorescent lighting. The wpg rule doesn't really apply to T5...

You could do 4 if you want, just hang it(not too sure on the height). Yes, you still get high light.

Right now my 75g has a Odyssey 54wx2 T5HO bulbs. But I was told it was only low light.

The bulbs are 6500k. I'm looking to be able to grow hair grass and other sorts. So would the existing light be enough?

I'm doing, MS for substrate and also plan on having pressurized CO2

I'm not going to repeat what everyone else has said so far, so I won't. But you should at least be aware that even if you use 4 bulbs, it will be high lighting. I think 4 bulbs should definitely be the max for this tank, or you're gonna have an algae farm.

T5HO is basically one of the brightest, most efficient sources of lighting on the market, watt for watt. The wpg "rule" has pretty much been shown itself to be useless when using T5HO.

It is hard to beat the deals for Catalina Aquarium 48" Solar T5. The 3 or 4 bulb fixture would be great.

i agree with yikes about the catalinas. once you factor in labor and tools and time wasted on building your housing/setup theres no real gain other than self satisfaction.

Take all the TO MUCH! light comments with a grain of salt.

^ What's that supposed to mean? Sounds to me like everyone is genuinely trying to help this guy.

It is possible that the Odyssea light doesn't have the typical great reflectors that most T5HO lights have, and that could cause you to have low light intensity with that fixture. But, typical T5HO lights, which is what we are referring to, do give high intensity for tanks that are 20 inches deep - two bulbs would do it if they could cover the full front to back depth of the tank. With a pair of two bulb fixtures, separated by a few inches, you would have high light intensity over the whole substrate. Even 3 bulbs, separated so they can cover the whole substrate uniformly would give you high light, at the low end of the high light range. Or, best of all, using more bulbs, but raising the fixture several inches above the tank would give you high light and much more uniform intensity over all of the tank.

RianS said:

i agree with yikes about the catalinas. once you factor in labor and tools and time wasted on building your housing/setup theres no real gain other than self satisfaction.

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Not necessarily true. My tank in progress is a 40G breeder. I only want to put 2 X 39W T5HO over it. All of the store bought twin tube T5HO lights have the bulbs about 1 1/2 - 2 inches apart. By building my own light fixture I can spread the bulbs about 6 - 8 inches apart and get more even light converage on a tank that is 18 inches front to back.

Besides time spent building something is never time wasted to people who like to build things.

As always, a lot of opinions to choose from. :fish:

Much of the awesomeness of T5 lighting stands and falls with reflectors. Good reflectors will direct a lot of light into the tank (where you want it). For T12/T8 bulbs, no such great reflectors are available, which adds to the opinions of superiority of T5 bulbs.

So, if you try to fit 8 bulbs into a 15" canopy, you will have trouble fitting the reflectors in it. Better to cut down on the number of bulbs, and get the most from it using good reflectors.

And just to add another opinion, I think 2 of those bulbs would be fairly low light for a 75gal tank, 3 medium, and 4 high light. Using first class MIRO4 or such reflectors it might shift up a notch, using no reflectors it goes down a bit.

Church said:

^ What's that supposed to mean? Sounds to me like everyone is genuinely trying to help this guy.

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Tnsser had a thread where he had 216W over a 55gallon. He raised the fixture and put a plexiglass lid on top of the tank, and this all cut his light way down. I think he's just saying that 6 bulbs isn't insane.

Or, he thinks you guys are a bunch of nuts. I'm not sure.

I was not trying to insult. It is just like any other subject or forum on the web. 1000's of different opinions.

tnsser said:

I was not trying to insult. It is just like any other subject or forum on the web. 1000's of different opinions.

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I'm not sure if the number of opinions about light is 100's, 1000's, or 10000's. I am sure that 2 years from now a lot of what most of us believe to be "the truth" about lighting will be embarrassing to us. And, that is probably true for 90+% of the opinions. There is just so much to learn and figure out. And, that makes it fun.

Hoppy said:

I'm not sure if the number of opinions about light is 100's, 1000's, or 10000's. I am sure that 2 years from now a lot of what most of us believe to be "the truth" about lighting will be embarrassing to us. And, that is probably true for 90+% of the opinions. There is just so much to learn and figure out. And, that makes it fun.

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PAR meters are going to be high on that list of snake oil. Maybe not snake oil, more like pH controllers. Useful but overpriced.

PAR meters, like drop checkers, are a good learning tool, helpful at times, but not needed for every day's activities. If you want to do any research that will be useful to others, a PAR meter is also very good. I would never consider buying one for my own use.

I wouldn't call them snake oil, just frills for most people.

Stay on topic folks.

http://www.marinedepot.com/lighting_fluorescent_sunlight_retrofit_kit_system-ap.html

There is not much cost savings in buying the parts separately if your going to use reflectors (which will be the bulk of the cost). These kits come with directions for wiring the lighting.

As far as building the shell of the fixture, are you somewhat handy with wood and do you have tools?

By the time you bulb and retro the kit though, it may just be more cost effective to buy a fixture. But this is up to you.