# Dual T5HO on a 40 gallon



## glenCOCO (Aug 12, 2012)

This topic has popped up hundreds of times but I always see conflicting answers. I have a 40 gallon tank that's 17" high and want to get as much light as I can without having to use co2. With a 36" dual t5ho 2x39w(not hanging) will I need co2? Some say yes, some say no. Which is it? If co2 is necessary, what other light options should I look into that would fit my needs? Can I get away with just dosing excel? 

Thanks in advance!


----------



## BruceF (Aug 5, 2011)

I have that light on a 40b. I ran it for quite a while with no co2. Algae was a problem especially with some of the plants. So it depends in part on what plants you grow, in part on how long you leave the light on and in part on what you use for a cleanup crew. I suppose it also depends on how you feed the plants. Lots of variables but it can be done.


----------



## glenCOCO (Aug 12, 2012)

What photoperiod worked best for you? I was thinking about having some red root floaters or frogbit. Would that make any difference? I guess maybe by blocking out some of the light as well as sucking up nitrates? I wasn't planning on getting a clean up crew, but was there any inhabitant in particular that made a significant impact on your fight against algae?


----------



## BruceF (Aug 5, 2011)

It is hard to say exactly, there are a lot of variables. I would start with around 8 hours of light and see what happens. Floaters would probably help. I don’t know much about cleanup crews because I don’t usually use any. Probably the most important thing is to avoid the plants that need high levels of co2 in the first place. Look through the low tech show and tell try and figure out plants that will do well. Make sure you use some fast growers. http://www.plantedtank.net/forums/showthread.php?t=99729


----------



## glenCOCO (Aug 12, 2012)

Browsing through that thread definitely helped out a lot! Thanks for all the help!


----------



## andrewq (May 22, 2013)

I also have a 40gal, with dual T5HO 39w. Im only using one bulb presently and it puts out 10000k 39w. It makes the plants stand out really well. I have a ton of java moss on driftwood, couple swords, anacharis, corkscrew val, java fern, and salvinia floaters. Im testing out light as I dont have co2 either. At least not yet, probably in the future. Alot of people have different opinions on adding co2. Lights been up for only a few days. The val, swords, moss and salvinia all have responded well to the lighting. Especially the salvinia. Im keeping and eye out for algae, and so far nothing. I am using root tabs, and dosing with excel every few days. Lights are not hanging either. They are sitting on top of tank about 2in above the glass top. 

If everything goes well, Im going to add a second bulb, probably 6500k. Sounds like our setups are similar and you have the same questions I had. Let me know how it goes, and I will do the same.


----------



## norbot (Jan 5, 2013)

If want nice lush growth and don't want to use pressurized co2, why do you want so much light? I am using 2x54w t5ho over a 55g but I had to suspend it 2 ft. above the tank, and that's using pressurized @ 15bps

Also keep in mind that all t5ho are not created equal. some don't use true "high output" ballast. I've noticed that my hagen glo is decidedly less powerful than my diy hd light

Edit: I think you could get away with that light and no co2 if you were to hang it. You could just start with the light hanging really high and gradually lower it until you see problems w/ plants or algae. Then you would know your approximate lighting threshold.

I personally prefer the look of a darker, deep green tank, with shadows coming into play.

I don't know if there is an answer to _needing_ co2. I've seen lots of light used successfully w/ no co2, and lots of light used unsuccessfully with co2

One thing I know for me, I love co2, once you're up and running it's pretty cheap and I believe it's the only reason I haven't killed all my plants, ha


----------



## glenCOCO (Aug 12, 2012)

andrewq said:


> I also have a 40gal, with dual T5HO 39w. Im only using one bulb presently and it puts out 10000k 39w. It makes the plants stand out really well. I have a ton of java moss on driftwood, couple swords, anacharis, corkscrew val, java fern, and salvinia floaters. Im testing out light as I dont have co2 either. At least not yet, probably in the future. Alot of people have different opinions on adding co2. Lights been up for only a few days. The val, swords, moss and salvinia all have responded well to the lighting. Especially the salvinia. Im keeping and eye out for algae, and so far nothing. I am using root tabs, and dosing with excel every few days. Lights are not hanging either. They are sitting on top of tank about 2in above the glass top.
> 
> If everything goes well, Im going to add a second bulb, probably 6500k. Sounds like our setups are similar and you have the same questions I had. Let me know how it goes, and I will do the same.


My planned setup, as far as plants go, seems very similar to what you already have set up. I'll definitely keep you updated.



norbot said:


> If want nice lush growth and don't want to use pressurized co2, why do you want so much light? I am using 2x54w t5ho over a 55g but I had to suspend it 2 ft. above the tank, and that's using pressurized @ 15bps
> 
> Also keep in mind that all t5ho are not created equal. some don't use true "high output" ballast. I've noticed that my hagen glo is decidedly less powerful than my diy hd light
> 
> ...


The reason I won't use co2 right now is due to money. I'm open to DIY co2, but i've read that at a tank this size, you would need so many bottles that it wouldn't be worth it. I want to be able to have "rapid" growth and some reds as well. Correct me if i'm wrong, but i'm assuming that having as much as light as possible without having to use co2 will help me achieve that goal. Since hanging isn't an option, should I be looking for a different fixture?


----------



## norbot (Jan 5, 2013)

Yeah you're right, I used 6x2L diy co2 on my 55, it helped but it was a lot of hassle.

There are other ways besides hanging to reduce light intensity. You could use legs that sit on the tank, or use window screen to cut down light.

I don't think you should change your fixture, having that much light gives you future flexibility if you get co2.

Have a look at this thread, they use high light for 24 hrs a day!


----------



## tithra (Dec 1, 2012)

I ran my 40B with a dual aquatic life t5ho for about 1.5 yrs without co2 or ferts, with the fixture right on the tank. Plants grew fine in general. I had issues with diatoms pretty consistently though and some BGA for a few months. 

I eventually decided that it was really too much light to be running on the tank without co2 and I now have a pressurized co2 setup and am doing EI dosing. The health and growth rate of my plants is so much better as compared to before, and I am able to now keep some types of plants that I couldn't before. 

If you look at Hoppy's pinned PAR charts in the lighting section that should give you a basic idea of how much light you have on the tank.http://www.plantedtank.net/forums/showthread.php?t=184368 For my aquatic life fixture I am falling in the 70-80 range (accounting for substrate height) which is certainly high light and really should have co2. That's not to say it can't be done without, but you may be inviting some algae issues and plants that are starving for co2 because of the amount of light they are getting. You could always use some floaters or window screen to cut down light if a bit if you want to continue using that fixture.

I am far from any sort of expert on this stuff so take this worth a grain of salt, but my understanding is that you are not necessarily going to get rapid growth in this setup because things are out of whack. With more light the plants are needing more nutrients and co2 to grow properly, if you do not provide these things and only provide a lot of light you may have plants that survive but not really thrive. My plants previous to my move to co2 and ferts survived and did okay, but now my plants grow rapidly.


----------



## Jonnywhoop (May 30, 2012)

I run a current nova 6 x 39w T5HO. I only use 4 bulbs with a +2 bulb noon burst. However my tank is only in DSM mode right now, so I cant say what my algae issues are. but my plants so far are booming!

edit: I will be using pressurized co2 and fertz btw.


----------



## exv152 (Jun 8, 2009)

You can always go with the two T5HOs on a 40b if you suspend the lighting.


----------



## glenCOCO (Aug 12, 2012)

Well, so far it looks possible. Thanks for the link, tithra. I guess it's just the start up cost of pressurized co2 that gets me. I can probably just take it slow and buy piece by piece, but that's definitely easier said than done. Until then, i'll have to depend on some frogbit and a little bit of light blocking ingenuity. 

Johnnywhoop, that's quite the setup you've got going there. Loving the "stump"!


----------



## glenCOCO (Aug 12, 2012)

Need a little help deciding which fixture I should go with. Both come out to about $55 so price isn't much of a deciding factor. 

http://item.mobileweb.ebay*com/viewitem?from=authbuy&itemId=160871683524

http://www.fishneedit.com/t5ho-3ft--2lamp-aquarium-light.html


----------



## Taari (Jul 31, 2010)

I have a 40 breeder with a home-made 36" dual T5HO fixture with parabolic reflectors. I suspended the light fixture about 9-10 inches above the rim of the tank and I still had to use CO2 or it would get over-run with algae.


----------



## glenCOCO (Aug 12, 2012)

Hmm, looks like I might have to rethink this. Here's a list of plants that I know i want to put into this tank. 

Crypts
Anubias
Vals
S. repens
Red ludwigia
Tiger lotus 
Amazon swords 
Frogbit

Considering what plants I want, should I be looking at different light? Maybe a single 39w t5ho? Maybe do what andrewq did and just run one of the lights?


----------



## houseofcards (Mar 21, 2009)

Does the light have two switches? Best scenario many times is to run the second light for just a short mid-day burst of an hour or two. This way the plants get some extra light if needed and it doesn't adversely affect algae growth. Many of the two bulb t5ho lights only have one switch.


----------



## glenCOCO (Aug 12, 2012)

That sounds like a perfect solution! Unfortunately the two fixtures I'm torn between only have one switch.


----------

