# When does CO2 become necessary?



## JamesHockey (Nov 10, 2010)

I think to keep it low tech you could go with the dual 17 watters


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## VaultBoy (Nov 11, 2010)

i have a 29g with a 2 x 18w T8 fluro i never had a problem with algae until i wired up a second ballast to overdrive the unit at double power.

and i only have a crappy home made cover not even a reflector. so IMHO that is about the max you can go without starting algae problems.


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## chicken (Aug 22, 2007)

Of all the options you list, I agree that the 2 x 17 watt fixture is your best option. All the others would be just begging for algae. I currently have a 55 watt PC fixture on my 29, and co2 is necessary.


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## chicken (Aug 22, 2007)

Prollydead said:


> By co2 I'm guessing you mean co2 injection. Otherwise co2 is always nessasary.
> 
> Be more specific when you ask questions.


I thought his question was pretty clear, actually.


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## lauraleellbp (Feb 3, 2008)

Rainer said:


> - 2x17w fluorescent
> - 2x24w HO T5 (1x 10000K, 1x "Freshwater" bulbs)
> - 2x24w HO T5 (1x 650nm, 1x 6000k bulbs)
> - 1x65w 6700K fluorescent
> - 2x65w PC w/lunar*


Out of those fixtures:

-2x17 T8 is low light
-2x24 watt T5HO is high light (you'll most likely need pressurized CO2, not just DIY) The first bulb selection would be for a freshwater tank, the 650nm bulb is actinic and for a saltwater tank.
-1x65watt would be low light
-2x65 watt would be at least moderate light- you'd do well to use Excel and DIY CO2 would probably be sufficient on the tank

What I run over my own 29gal low tech you don't have listed; a 2x18 watt Coralife T5NO: http://www.bigalsonline.com/Fish_Li...eries-Double-Linear-Strip-Lights.html?tc=fish


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## Rainer (Jan 30, 2011)

Thanks for mentioning that, Laura; I'd completely overlooked it. 

Trying to rank the lights in terms of power was confusing until I found an excel spreadsheet online which measures LSI. I plugged in the numbers and found for half depth:

2x17w T8 = 5.65 Medium Light
2x18w T5 NO = 6.57 Medium Light
1x55w CF (Chicken's light) = 7.53 Medium Light*
2x24w T5 HO = 7.8 Medium Light
1x65w CF** = 8.9 Medium Light
2x65w CF = 17.81 Bright Light

* First one where CO2 is mentioned as necessary
** Actually a compact 6700K; the product description was unclear.

So it looks like Laura's setup is the best option to maximize lighting without adding CO2. 

Unless someone has another suggestion?

If not, it's time to start looking at plant possibilities: some sort of carpeting and maybe a floating riccia mat partially covering the surface. But that's another thread.

Thanks for everyone's helpful suggestions! It was a frustrating process until I found this board.


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## Rainer (Jan 30, 2011)

lauraleellbp said:


> -2x24 watt T5HO is high light (you'll most likely need pressurized CO2, not just DIY) The first bulb selection would be for a freshwater tank, the 650nm bulb is actinic and for a saltwater tank.


I thought I'd made a mistake, but that is actually listed as a freshwater setup and discussed in a current thread.




lauraleellbp said:


> What I run over my own 29gal low tech you don't have listed; a 2x18 watt Coralife T5NO: http://www.bigalsonline.com/Fish_Li...eries-Double-Linear-Strip-Lights.html?tc=fish


 Also in another thread someone mentioned these are being discontinued. I haven't had a chance to check - anyone know for sure?

Or have other suggestions?


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## lauraleellbp (Feb 3, 2008)

There was talk of the Coralife T5NO being discontinued a year or so ago, Big Als had even put them all on clearance, but then it didn't happen... so IDK?

I'll be sorely disappointed if they do- there's no other fixture on the market right now in that same light level, the only alternative is to DIY your own fixture with T5NOs from a hardware store.


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## Rainer (Jan 30, 2011)

Is that light really really green? I installed it today and the tank looks like a benthic algae farm. Nothing growing on the plants; only a very thin film on the glass; water is not cloudy.

I have been feeding the bamboo shrimp a dissolved algae tab daily though, so it could be that too.


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## BBradbury (Nov 8, 2010)

*Basic Lighting Info*

Hello Ranier. There's really no mystery to basic tank lighting. I have several large, well planted tanks and have never used CO2, to me it's too expensive. 

I use moderate lighting and get by with less than one watt per gallon. I use tubes in the 6,500 K (Kelvin) range and typically T8s for my larger tanks and T12s for the smaller ones. The 65K tubes are recommended for the standard planted tanks because the light blue tint best mimics natural daylight. You can get these at most of the chain hardware stores for about eight to ten dollars a piece. Avoid the LFS, their tubes are the same, but much more expensive.

I think moderate lighting requires the use of a good liquid fertilizer too. Nutrafin and SeaChem have some good products, though a little pricey. I personally use Cidex, but that's another story.

Once you have your lights in place, you'll need to choose plants that grow well in moderate light. If you'd like a list, just let me know.

BBradbury


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## Diana (Jan 14, 2010)

As long as you are thinking about the T-12 and T-8 bulbs, somewhere around 2 watts per gallon is the cutoff. When you start thinking about better bulbs (proper plant wavelengths, T-5), and custom fixtures (well designed reflectors) you get into pressurized CO2, even when the watts per gallon look low. 
I run most of my tanks with a plant bulb and a 'daylight' or 'cool white'. T-12 or T-8. 
This way I know there is something for the plants, and a wider range so the plants and fish look natural to me.


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## Rainer (Jan 30, 2011)

I


BBradbury said:


> Once you have your lights in place, you'll need to choose plants that grow well in moderate light. If you'd like a list, just let me know.


 Thanks for the suggestions. I posted a list of plants I'm interested in on another thread on this forum if you'd like to take a look.

I'd include a link but it's a pain to do on this phone.


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## JeffHB (Feb 11, 2011)

I have a 29 w/standart 17W 6500lamp and could get a little growth from java fern and apogen's - no algea problem. I upgraded to a hardware store bought 24watt T5 strip light and just removed the ballast and retrofit it into my existing tank light (using same on/off switch), now have a 24W 10k AND a 17W 6500 (same enclosure)...had some algea at first (like you mentioned), then cleared up but I also dose XL. too early to tell how effective it will be...


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## Rainer (Jan 30, 2011)

lauraleellbp said:


> What I run over my own 29gal low tech you don't have listed; a 2x18 watt Coralife T5NO


 Is it mounted directly on the canopy or raised/suspended?

I just noticed that mounted flush it's considered high light.


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## lauraleellbp (Feb 3, 2008)

Mine sits directly on top of a glass canopy. I think between the poor reflector design, how the bulbs sit right next to each other in the fixture, and the light diffusion coming from the fixture cover and my glass canopy, I find the light level perfect for a non-CO2 tank.


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## Rainer (Jan 30, 2011)

Whew, thought I'd neglected a critical point there. I'm still using the black Aqueon hood - not sure how that compares to yours. Guess it's even weaker.

Does this mean medium-high light plants are an option?


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