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Absntmind 04-26-2012 04:57 PM

Too much light?
Hello all, first post here so please forgive any mistakes :-). I have a lighting question and was hoping someone here could help. Been a long time since had an aquarium, and even then it was kept really simple.

Just finished getting a tank set up; 55 gallon (48"x13"x21"), sand substrate, fluval 405 canister filter. I want to do a planted tank, so was in search of a hood to replace the old one. I came across what I beleive was a good deal as far as price, so jumped on it. It is a Current USA T5 8 bulb. I don't recall all the specs, but am planning on searching by model once I get home.

I set it up last night, flipped the switch, then waited for my sight to return... I was originally thinking of getting a light with only 2-4 bulbs, yet when this one came across for the same price my thoughts where it couldn't hurt. It has two switches, so I can run 6 instead of all 8.

My question being, does anyone have suggestions as far as bulb types to spread across the six? I wasn't sure if there is such thing as too much light for the fish as far as bulbs/watts go, and if so, maybe there is a combination to use so that neither fish nor plants will be negatively affected. Is this light fine to use, should I start looking for something smaller, or am I over thinking this? Fighting a huge learning curve here, and appreciate any help.

Byron 04-26-2012 06:36 PM

First, welcome to Tropical Fish Keeping Forum.:-D

Now, by 8 bulbs i will assume that you mean fluorescent tubes, since you term it T5. This is designed for marine reef tanks and will be way too much light. Even if you could get them down to only two of those tubes lit, it would be too much unless then you are planning a high-tech with diffused CO2 and such.

This is going to be very problematic; can you return it or exchange it? Over a 4-foot 55g tank you have three options: a single tube T8 fixture, a single tube T5 fixture, or a dual tube T8 fixture [in all three, taking 48-inch tubes]. Option 2 (a single tube T5 with an HO tube) is probably the best, though a dual tube with T8 will work with reduced duration. Assuming a natural (low-tech method) planted tank.

Overhead tank light is stressful on fish if it exceeds a reasonable level; what I've suggested above are reasonable levels, assuming floating plants too. Beyond this, there is the matter of algae that will take over when light is beyond the capacity of plants to utilize.


Absntmind 04-26-2012 09:45 PM

Hi Byron, thank you for the response.

Yes, 8 fluorescent tubes. That's what I was afraid of, being to much light. I was under the misconception of the old gallon / watts rule, and that I might get by with only running a "little extra" with 6 lol. I can't return it since it was a craigslist purchase, but I should be able to sell it at a local store that sells/buys used aquarium equipment. I think I got a good enough deal to at least get my money back.

I'm surprised a single tube would be able to put out enough light to grow plants in a tank that size. Do you have any specific fixtures you would recommend? I want to grow some low-medium light plants/moss, and keeping the tank moderately stocked.

Once again, thanks for the help!

Geomancer 04-27-2012 06:24 AM

Yes, a single T5HO over a 55 gallon is more than sufficient for what you plan. A fixture like that is going to be hard to find though, most come as a dual T5HO or four tubes. Some of the dual T5HO fixtures will work with only a single tube in it, but some won't. You'd have to research that and I'm afraid I don't know any off hand.

Mosses grow well under low light, a single T8 is more than enough for them and that's likely what your tank came with. A dual T8 fixture you can get at Home Depot or Lowe's for $17 (that's how much my 48" dual T8 was). It will be a shop light, but works the same.

I'm using that fixture over a 6 foot, 125 gallon aquarium and it's pretty bright in there, more than enough for low-moderate light plants. The corners are darker, because there is a foot with no light on each end, but still enough light for low light plants in those corners.

Depth is really the key, not the gallons. A 55 gallon is 21" deep. My 125 gallon is 23 3/8" deep. So only a difference of 2 3/8" which isn't much at all.

Here is a picture

Absntmind 04-27-2012 09:07 AM

Hello Geomancer,
As for what the tank came with, it was in really bad shape. This is my girlfriends’ tank, and it was up and running when I moved in. We decided to clean it, update the equipment, and try planted. So the first thing we got rid of was the light fixtures and broken canopy. I replaced the top with a glass canopy, which is in two pieces due to a support bar that runs down the middle of the tank.

Unfortunately, hanging is out of the question due to the way the room is (suspended type ceiling and tank already close to wall). I like the way that looks, so it will definitely be something to consider once we move.
All of the T8 fixtures I have seen that don't suspend seem to sit on the canopy. With my setup of glass tops and that thin plastic strip, would it be safe and/or even efficient to use that type? Or would I be better off just getting a dual T5?

Also, there has been no mention of wattage. I understand that the old adage doesn't work, but I still assume makes some difference. I've seen T5 lights that are 24w-54w, and the same with T8. Is there a certain wattage I should go with depending on if I get single or dual?

Geomancer 04-27-2012 09:36 AM

You described my tank exactly ;)

I have the Aqueon glass tops, they are hinged at about 1/3 the width and the last two inches are plastic that can be cut for hoses or wires. Mine has two plastic center braces versus your one, but that's because the tank is 2 feet longer.

The shop light I use has reflectors that curve down along the sides, so when it is sitting on top of the glass the bulbs themselves do not come in contact with the glass. I do not hang it from the ceiling, or a canopy, it's just resting on the glass.

I think this might be the one I got, but can't be sure from the picture. Something similar though: Shop Utilitech 48" Utility Fluorescent Lighting at

Now for wattage ... that's actually I think pretty much fixed. The variation you see is usually due to a variation in the length of the tube. For example, a 48" T8 will be 32 watts. With T5's you have to look closely, there is T5 and then there is T5HO. Both are the same diameter, but the T5HO is a high output version, which is what the HO means. If you didn't know, the T number is the diameter in eighth's of an inch. So a T8 is 8/8" or 1" while a T5 is 5/8" diameter.

A dual T5HO on a 55g will likely be 'high' light, and you may struggle to find a balance without the use of CO2 injection. If the system isn't in balance, you'll create an algae farm. You might get away with it if you have heavy floating plant cover, but I don't have enough experience/knowledge to say if that's true.

Absntmind 04-27-2012 10:17 AM

OK then, that helps out a lot! I'll be making runs by my local stores today and hopefully can find something (my city is horrible with hobby/specialty stores), maybe even a trip by lowes :)

Thanks for the help guys, I'll let you know how it turns out.

Byron 04-27-2012 10:27 AM

I really would not get a dual-tube T5--unless you can find one that will allow only one of the two tubes to be lit. I tried a dual-tube T5 for a week over my 5-foot 115g (with 2 48-inch tubes, so exactly what would be over your 55g with a dual T5) and it was so bright I thought my poor fish would be asking for sunglasses. After using it a week i took it back and got a T8, dual 48-inch tube. I have this same light over the 4-foot 90g and 4-foot 70g. Over the 70g it is obviously more intense light, and this would be much what you would see. So this is what I consider the absolute max for a 55g. I have algae problems in the 70g which I don't have in the other two.

Watts is rather meaningless as Geo said. It all depends on the phosphors inside the tubes, and today manufacturers are making more energy-efficient tubes so they produce more intensity for less energy, and watts is simply the measurement of energy used regardless of the light resulting. The only time watts is relevant in comparisons is between identically-made tubes/bulbs. For example, a GE daylight CFL at 13w will obviously be a bit brighter than the same bulb at 10w. But comparing a 40w Phillips 5000K tube with a Life-Glo 6700K 32w tube is comparing apples and oranges, and in this example the Life-Glo is the brighter.

As Geo also mentioned, T5 comes in NO and HO. The NO is basically identical in output to the same type of tube in T8, so it is less common to find. I assume no one would pay more for T5 NO when they can get the same thing for less in T8. The HO and now VHO is the advancement in T5 that is prevalent, because these were designed for reef tanks so more appropriate bright light for corals could be obtained with fewer tubes. Their use over planted tanks is very limited.

I did once find a single tube T5 fixture online for someone, but it was a clearance so I assume this is something that didn't sell and is disappearing. For a 55g I would consider T8, and then single or dual tube. I had a single tube T8 over my 55g many years ago, and when tubes were few and far between and no where near as efficient as now. I used a T12 Grolux which is very weak light, but I managed swords and floating plants.


Termato 04-27-2012 11:52 AM

Um....I wanna make sure I don't have too much lighting too now lol

29G - F20 6500k Fluorescent Bulb (20 watts) and a 23W 6500k CFL Bulb.
20G - F15 6500k Fluorescent Bulb (15 watts) and a 23W 6500k CFL Bulb.

The CFL's are much brighter than the fluorescent

This is the CFL Bulb: Shop SYLVANIA 2-Pack 100-Watt Equivalent Daylight Compact Fluorescent Light Bulb at

I did this to the 20 gallon and the 29. It's the stock overhead light and a desk lamp with the new bulb in:

Is this too much light?

TwinDad 04-27-2012 11:55 AM

I've seen both single T5ho, and dual T8 as long as you are willing to shop online. As far as pet stores go, I've seen single T8 at both Petco and Petsmart in a 48" hood.

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