# What is the difference between T5 and T5HO?



## HammerJoe (Jul 15, 2005)

I am looking at getting some decent lightning for my new 75gal.
I decided I wanted to have around 200W of lightning.

I can go the diy with ODNO, or I can get two of those T5 or T5HO systems now available.

What is the difference between the two and as bang for the buck is concerned which one is better?


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## BlueRam (Sep 21, 2004)

Good questions.

A 4' T-12 uses 40 Watts and emitts ~2775 lumens.
A 4' T-5 uses 28 Watts and emitts ~2900 lumens. 
A 4' T-5(HO) uses 54 Watts and emitts ~5000 lumens.

So basically the T-5 is a more efficent bulb in that it puts out ~the same amount of light for less energy. The T-5HO uses more power and emitts more light but the efficiency (Lumen/Watt) is not linear. I included a T-12 so you can go back to WPG in T-12 (the "standard").


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## HammerJoe (Jul 15, 2005)

Thanks for the info.
Based on your 
T5HO seems to be the best option.

I am not sure how many lumens a 75gal, 20 inches deep requires, but would a fixture with two T5HO be enough (10000lumens)?

What are your thoughts on this?


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## Wasserpest (Jun 12, 2003)

Two of them 54 Watters would be low light levels. Three would probably be good for most ppl, with four you step into higher light territory, with CO2 and regular fertilizer dosing required.


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## AaronT (Apr 11, 2004)

HammerJoe said:


> Thanks for the info.
> Based on your
> T5HO seems to be the best option.
> 
> ...


A lot of this also depends on how good your reflectors are. I've heard that many people like the Sunlight Supply Tek T5 fixtures. The 4x54 watt would be ideal for that size tank.


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## mik778866 (Aug 22, 2014)

BlueRam said:


> Good questions.
> 
> A 4' T-12 uses 40 Watts and emitts ~2775 lumens.
> A 4' T-5 uses 28 Watts and emitts ~2900 lumens.
> ...


 Hi. Found this old post whilst googling.

Based on the above statement, will it be correct to say that 2 * 4' T-5 is better than 1* 4' T-5(HO)?

If this is the case, purchasing more T-5 normal output is a sensible thing to do, as these are much cheaper.

Not sure of PAR readings though. Any input?

Regards 
Muhammed


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## jeffkrol (Jun 5, 2013)

mik778866 said:


> Based on the above statement, will it be correct to say that 2 * 4' T-5 is better than 1* 4' T-5(HO)?
> Regards
> Muhammed


all other things being equal yes that is correct.
Though the 10 lumen/watt "penalty" of t5HO's is pretty much in the "margin of error" in an overall system..
As to PAR the red and blue bottom lines compare a Corallife T5 and T5ho 2 tube fixture:









To get equal PAR (w/ roughly equal watts) you would need a 2:1 ratio of t5no to t5ho.


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## roadmaster (Nov 5, 2009)

I would not call two 54 watt T5's on 75 gal tank low light .
Maybe poor light spread due to width of tank, and or close spacing of bulb's in most dual light fixtures, but certainly not in my view ,low light.
PAR at 35 to 50 at substrate will grow most anything with or without CO2 enhancement.
My two cent's .


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## cjp999 (Nov 18, 2008)

roadmaster said:


> I would not call two 54 watt T5's on 75 gal tank low light .
> Maybe poor light spread due to width of tank, and or close spacing of bulb's in most dual light fixtures, but certainly not in my view ,low light.
> PAR at 35 to 50 at substrate will grow most anything with or without CO2 enhancement.
> My two cent's .


Agreed. I have 2 T5HO on my 46g bow, and it's definitely not low light. I'd consider it med/high. I also agree on the spread issue. Getting light to the front of the tank is hard, especially when tall plants starts to fill in the back. That dark strip down the middle of the glass cover forces you to keep the light more towards the back of the tank.


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## mik778866 (Aug 22, 2014)

jeffkrol said:


> To get equal PAR (w/ roughly equal watts) you would need a 2:1 ratio of t5no to t5ho.


Thanks for your response. What do you think would be the ratio of a t8 to a t5ho?


Sent from my ALE-L02 using Tapatalk


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## jeffkrol (Jun 5, 2013)

mik778866 said:


> Thanks for your response. What do you think would be the ratio of a t8 to a t5ho?
> 
> 
> Sent from my ALE-L02 using Tapatalk


t5,t5ho,t8 all have about the same output efficiency w/ t8 holding a slight edge..
so really it is all based on watts/tube ratios..


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## yashar (Oct 17, 2016)

T5 ballast drives T5HO? HOW?
(becaues I can not find HO ballast for my "sylvania FHO24w/T5/865" in my city)


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## jeffkrol (Jun 5, 2013)

yashar said:


> T5 ballast drives T5HO? HOW?
> (becaues I can not find HO ballast for my "sylvania FHO24w/T5/865" in my city)


just a matter of amperage output of the ballast..But I'm not guaranteeing this..5/t5ho bulbs are, err, "generally" interchangeable..
The catch.. putting t5 bulbs on a t5ho ballast will "overdrive' the bulb shortening lifespan.
putting t5ho bulb on a t5 ballast will "underdrive" the bulb..

you can get all sorts of odd effects from dull lights, shifts in spectrum, to short life.
some of this is ballast specific, w many electronic ballasts being "forgiving" in nature..

Always best practice to use the correct ballast w/ the correct bulb..

http://www.lrc.rpi.edu/programs/nlpip/lightingAnswers/lat5/pc1a.asp


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