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I ask as I just bought a 4x39 watt T5 enclosure with reflector.

its going onto a 75g tank. Is this going to give out more light than a normal fluro tube?

Hi,

You don't say what brand reflector you have purchased so
we cannot look it up and read the specifics about that
unit.

Generally speaking, 4x39=156watts/75G= 2.08 watts per gallon(wpg)

That gives you enough light for the low light demand plants
and many of the medium light demand plants.

Since T-5 bulbs are 5/8 inch in diameter and your
enclosure holds 4 of them thats roughly 2.5 inches of bulbs.
Normal fluorescent bulbs are T-8 or T-12 meaning that the
diameter is one inch, and inch and a half in diameter.
The Normal fluorescent bulb is 40 watts max and a similar
hood that held normal fluorescents would only hold two bulbs
or 80 watts giving you less than a watt and a half. That
would restrict you to barely having enough light for some
low light plants.

If the tank is a show tank, a "tall" tank, then you might
think about using the higher "K" rating bulbs, perhaps as
high as 10,000K. That will give you more energy reaching
the substrate surface than the lower "K" rating bulbs.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

T5s are generally considered to give out the most lumens per watt aside from maybe MH. That means it will count as slightly more light than NO fluorescents and even than compacts. The reason compact bulbs are more popular is that T5s have to be replaced very frequently, are expensive, and produce alot of heat. A T5 bulb should be replaced every 6months at least and some suggest every 4months where compact bulbs can last a year or slightly over. Marine aquarists with money to burn really seem to like T5s though since they do put out more light than other fluorescents.

Got your facts wrong sham

T5 bulbs last longer and run cooler than than PC(alot! believe me I have both). On a reef tank I'd switch PC bulbs at 10 months if I could afford it. T5's run cooler (aren't doubled over on themselves) and therefore run more efficiently and last longer. I've seen great coral growth on T5 bulbs that were 18 months old. Most T5s will still have a large percent of output until they fail.

Also, the reason they "put out more light" compared to a power compact is because of how skinny the bulb is. When a reflector is made individually for a T5 bulb it more closely resembles a parabola than with power compacts. This means more light is reflected into the water than back into the bulb, also creating less heat. The actual bulb probably doesn't put out much more light than a power compact. That is why it is crucial to get a fixture with individual parabolic reflectors for each bulb rather than one large reflector. With individual parabolic reflectors, T5s can easily double or more the light output per watt of a compact fluorescent.

I'd also like to add that I had 2x96w PC on my 30G reef tank and switched to T5s. I've finally figured out that even 4x39 watt T5s are too much light. I simply have 2 39W bulbs over a reef tank with healthy thriving corals. That's less than 3 watts per gallon.

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Critical Fertilator: The Micromanager of Macronutrients

ok forgot to look at the light when I got home but I looked at the online ebay store I bought it from.

its a sun sun HFL-1200.

The tank is 2ft tall. Does this count as a 'tall tank'?

Oh yeah and thanks for the info guys.

Hi Troy,
Yes two feet deep is a "tall" tank in that the light has
to pass through nearly two feet of water before it reaches
the substrate. That amount of water can scatter the light
and absorb some of the energy.

The bulbs sound like they would be good.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

I am really looking forward to planting this tank.

While Im here, is there any suggestions on a Co2 set up?

I usually rig up a cokebottle with sugar and yeast on my 30 gal tank but this is a bit bigger. If I were to go to proper Co2 injection, how long do the gas bottles last?

I would recommend you go with pressurized on a larger tank like a 75. With a couple or 3 bubbles per second the CO2 tank will last a few months, give or take. You can get the tank at a local welding supply store, and the regulator I would recommend would be a milwuakee regulator. Many of us use those with good results. They can be found all over the place on-line. I actually have an LFS good enough that got one in for me (cheaper for me because I work there, might be cheaper for you to shop online).

Oh, I also wanted to make clear that I was talking about T5HO lighting being brighter than power compacts when used withproper individual parabolic reflectors. I believe though that you can only get 39w bulbs as T5HO 3ft bulbs. So that should all apply to you, the bulbs should just be offset, so the center will be a little brighter. That would be my guess.

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Critical Fertilator: The Micromanager of Macronutrients

Hi,
The general rule of thumb seems to be a 30G cutoff for
using DIY CO2 injection. Larger tanks require more coke
bottles in series, and many more waiting in reserve.
Then you add your own schedule into the mix and the CO2
in the tank goes up and down as family schedules get in
the way of keeping the bottles mixed, fresh, and connected.
In short, it turns into a real CHORE. The plants suffer
too as they shift between feast and famine.

When you first set up your bottled system a good safe
start is with one bubble per second and watch your pH.
(An electronic pH monitor is an excellent investment at
this point) Watch the CO2 saturation (pH vs KH readings)
for 12 to 24 hours and then adjust up to 2 bubbles, and
wait, etc. In other words adjust slowly over time watching
the pH/KH readings till you get to about 30mg/l CO2
saturation.

My 5 pound bottle lasts for about 6 months at 2 bubbles
per second and costs 10$ plus tax to refill.
Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Then all the people I've talked to are wrong because I've always been told to replace T5s within at least 6months and that they produce tons of heat. It's the 2 most common reasons I see people state for choosing PC over T5. Despite the fact all the people I see using them say they put out more and better light than PCs.

Dunno if all the people you have talked to have read this thread. I suggest you do. When you read all 260 pages come on back and we'll talk.

This here's from a guy who sells and uses ALL kinds of bulbs and has done so for years, so he knows more than you and me.

Originally posted by Aquactinics
Ok. I see there is still some confusion about the workhorse ballasts. Let me see if I can straighten some things out. The Workhorse ballasts are solid-state ballast. They are hard start ballast, this is true. In tests, T5 lamps on a solid state ballast have in about 50% of the lamps tested shorten the overall T5 lamp's life by around 20% ( or somewhere around that ). Now, what does this mean to someone using them for reef tanks? Not a whole lot. A T5's lifespan is around 25,000 hours ( at 12 hours per start ) So, at 12 hours a day, 365 days a year that comes out to 5.7 years. For a solid state ballast take 20% off the and you get about 4.56 years ( and that's for only half the lamps ). For reef tank use, just like MHs, the bulbs are not used for it's entire lifespan. T5s are typically used for about 18-24 months depending on color type and brand. But again, it all depends on the bulb. I know some that change it sooner and some the use it much longer. A solid-state ballast versus a programmed start ballast all comes down to the starting of the lamp. Unless you are going to start the T5 lamp on workhorse ballast 10 times a day, you are really not going to see much of a difference in the T5's life.

I know it's just one guy, but if you read the thread there are quite a few people who agree and not too many that disagree. My bulbs personally have been running for 7 months. I'll let you know how they are doing a year from now.

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Critical Fertilator: The Micromanager of Macronutrients