# Do I need another lighting fixture?



## luananeko (Aug 27, 2010)

Hi all! I'm in the process of getting a 75 gallon planted tank ready to upgrade from my 30 gallon planted tank and I wanted to check if I had enough light... I picked up a GLO T5 HO fixture that takes two 48" bulbs and have a 6700K 54W and a Colormax 54W bulb installed in it, running 10 hours a day. I've started emersion planting my foreground Dwarf Baby Tears, Glosso, and Anubias Nana Petite to give them a chance to take root before I fill the tank and start cycling. Will this still be enough light once I fill the tank? Where do I fall on the lighting scale? I'm guessing medium, but I was told by another member that I don't have enough light for any foreground plants... Do I need another fixture, or is there some way to add stronger bulbs?


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## jbrown5217 (Nov 9, 2011)

Basically you are running low light. At least from my limited understanding of plants. Low light is considered >= 1 watt per gallon, medium light is <=1 watt per gallon but > 2 watts per gallon. High is < 2 watts per gallon. Although I did read an article somewhere that explained something about lumens and that wattage isn't the most important factor. I'd do a google search to try and find that article.


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## luananeko (Aug 27, 2010)

Low light? Even though I have a high output fixture instead of a standard one? I thought the whole point of the HO fixtures was that they did 3x the normal light? Or was that just a sales gimmick :s ?

Edit: Oops, apparently I was remembering the wrong numbers. The bulbs are 54W each. Fixing original post


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## FishFlow (Sep 13, 2011)

Can't use the standard watts per gallons when talking t5ho's. 

Your 75 is 4' long? 24" tall ? 

2 t5ho bulbs ~ 24" above substrate is considered high light. (Look on plantedtank.net under the lighting forum) Got Co2 ?

High light brings it's own set of issues. 1 is you should be on co2, or you'll be growing algae.

Now if the fixture is of poor enough quality, maybe you are in the medium range. Also raise the light up off tank if you can't keep algae in check.


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## luananeko (Aug 27, 2010)

FishFlow said:


> Can't use the standard watts per gallons when talking t5ho's.
> 
> Your 75 is 4' long? 24" tall ?
> 
> ...


Okay, that's more like I was expecting to hear, I was a little surprised when I was told on a plants for sale thread that my lighting was considered "low light", even when I misremembered the wattage as 32W each 

I believe I have pretty close to the standard 75 gallon dimensions, so 48.5" long, 18" wide, 21" high with around 3 inches of substrate (higher in back, lower in front) unless my memory is failing me (which is highly possible). The light lays right on top of the glass top right now, but it did come with some brackets for raising it, just have to remember where the heck I put them. 

I was not planning on running CO2, but if my army of snails, ottos, BN pleco, and dwarf chain loaches can't keep up with the algae then I might try co2. I'd have to do some research though, as I've never messed with it before. Any nooby tips you have on that or guides you can point me to would be appreciated


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## debisbooked (Jan 7, 2012)

luananeko said:


> Okay, that's more like I was expecting to hear, I was a little surprised when I was told on a plants for sale thread that my lighting was considered "low light", even when I misremembered the wattage as 32W each
> 
> I believe I have pretty close to the standard 75 gallon dimensions, so 48.5" long, 18" wide, 21" high with around 3 inches of substrate (higher in back, lower in front) unless my memory is failing me (which is highly possible). The light lays right on top of the glass top right now, but it did come with some brackets for raising it, just have to remember where the heck I put them.
> 
> I was not planning on running CO2, but if my army of snails, ottos, BN pleco, and dwarf chain loaches can't keep up with the algae then I might try co2. I'd have to do some research though, as I've never messed with it before. Any nooby tips you have on that or guides you can point me to would be appreciated


Ha! I too have those light brackets if only I could remember where I put them. I'll be following this thread; I have a 75g planted and thinking of upgrading lights and adding co2. I've done some research but it just gets more confusing the more I read....*old dude


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## jrman83 (Jul 9, 2010)

You will definitely be somewhere along the line between high and medium lighting. Not all fixtures are created equally. Some T5HO fixtures will put out near 4 times what they are rated at because of the reflectors.

If you told someone that you had 2-32W bulbs it would be low light for a 75g. T5HO doesn't come in a 32W, they are all standard and it would be easy to deduce that you had T8 lighting at that point...which would be low lighting.

You can put in all the critters you like that eat algae with that light and it won't matter. There are many forms of algae and they may do well on the nice green stuff that will shows up on your glass, but most will not do so well on the BBA that will cover your plants - especially with a 10hr light cycle. It can also kill your plants.

You will more than likely require CO2 to keep your plants from being overrun with BBA, unless you have a 5hr or less light cycle per day, but that is just a guess. You may also need to look into dosing with ferts because of the light.

Bascially, what happens is the higher light level causes the plant to grow (no surpise there, right?), but when this happens in an excellerated environment that the high light creates, you need things like CO2, micro and macro ferts to keep up with the plants new growth rate. If all of the plants needs are not met for as little as one day, you can have BBA start and plant stunting going on. If it were me, I would get something less. Keep it if you like the black stuff on your plants. CO2 and ferts will be the only way you'll keep it from occuring....you may get away with it for a little while, but eventually......

Fishflow pretty much covered it. As he said, raising the light, which reduces the overall lighting, may also be an option.


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## luananeko (Aug 27, 2010)

debisbooked said:


> Ha! I too have those light brackets if only I could remember where I put them. I'll be following this thread; I have a 75g planted and thinking of upgrading lights and adding co2. I've done some research but it just gets more confusing the more I read....*old dude


I know what you mean, there's so much info it sort of overwhelms you when you're getting started 



jrman83 said:


> You will definitely be somewhere along the line between high and medium lighting. Not all fixtures are created equally. Some T5HO fixtures will put out near 4 times what they are rated at because of the reflectors.
> 
> ...
> 
> ...


Ahhh that makes much more sense, thanks! The light I have does have a reflector that covers the entire curved interior of the fixture, and it came pretty highly recommended, so I'm guessing that means it's one of the nicer ones? I'll definitely look into getting a CO2 system then, and I'm already using the Flourish liquid fertilizer, Flourish Iron, and Flourish Excel additives (usually once a week). I'm pretty new to the whole planted tank world, as I've only had my 30 gallon tank planted for a little less than a year. So much to learn!


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## Mr_Pat (Apr 13, 2010)

lols ok well after reading this i now know that our lighting is at <INSANE> level 2 6700 K bulbs 1 X 3000K and one deep blue marine light for color.. the thing about our light is the reflector.. each bulb has its own and it seems to shoot the light into the tank pretty good.. its the 4 bulb t5 ho fixture from Homedepot online.. 132.50 shipped with 4 6700K bulbs. fits perfect above 4 foot by 18 ish inch foot print tanks. currently having to dose with flourish excel to keep algae down as CO2 system still isnt done


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## jrman83 (Jul 9, 2010)

Mr_Pat said:


> lols ok well after reading this i now know that our lighting is at <INSANE> level 2 6700 K bulbs 1 X 3000K and one deep blue marine light for color.. the thing about our light is the reflector.. each bulb has its own and it seems to shoot the light into the tank pretty good.. its the 4 bulb t5 ho fixture from Homedepot online.. 132.50 shipped with 4 6700K bulbs. fits perfect above 4 foot by 18 ish inch foot print tanks. currently having to dose with flourish excel to keep algae down as CO2 system still isnt done


Yeah, 4 bulbs is way too much. You may be able to keep algae at bay for a little while but it is just a matter of time. You may be able to get away with 3 bulbs, but 4 is crazy IMO. Also, bulbs outside what plants need could stimulate algae that you won't be able to control. Keeping the 3000k and actinic bulb operating is fighting algae from a light that your plants gain no benefit from. I would try a 10000k bulb and see if it gives you what you want and turn the other two off. 10000k bulbs are good for plants.


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## Rufus' Mom (Jan 2, 2012)

Bummer. The light fixture you described in this post is exactly what I have. I was going for low light, low tech, but I guess I missed that boat. No wonder the plants are doing so well so soon. Now I'm looking into CO2.


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## Mr_Pat (Apr 13, 2010)

unfortunately with this fixture unless i just remove a bulb i cant run just 3.. theres 2 switches.. one for each pair of bulbs. and the 2 6700 bulbs seem to be plenty for our plants.. all kinds of growth. the algae is already gone after the excel dosing. i run the 3k and the deep blue actinic on the early hours of the day. and in the evening . actually makes for some nice evening viewing .. really brings out the colors in our tetras


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