# 90 gallon T5 lighting question



## whitetiprs (Aug 28, 2009)

I have a 90 gallon tank that I plan on doing as a heavily planted discus tank. I was wondering how many T5 bulbs I would need over the tank to give sufficent lighting all the way to the bottom. When I bought the tank it already had a dual strip coralife T5 fixture that I plan on using and was looking at either another 2 strip or a 4 strip. I will be using a pressurized CO2 setup on the tank as well.

Thanks for any input.


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## gpodio (Mar 16, 2010)

Might be worth getting the 4 tube fixture, this way you have the flexibility of having 2, 4 or 6 lamps on at once... If you were to get a 4xT5HO you may not even need the existing 2xT5 fixture... 2WPG would be my goal personally for such tank.

Hope that helps
Giancarlo Podio


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## Nue (Dec 27, 2009)

You could probably get away with what you have. T5 WPG rules isn't very good. I use 2x54w t5 on a 55g, and thats still to much. Im having to drop down to 6 hours a day to avoid algae.


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## NJAquaBarren (Sep 16, 2009)

depends on what you want to grow and how much growth you want. I have 2x T5 on my 84G (26 inches deep) and virtually everything gorws fine. 

-I do NOT have a carpet, but 6 inch tall plants do well
-Stem plants like C.Furcata grow well, have good color, but get a little leggy.
-Growth is fast. At this stage I am trimming heavily every 2 weeks.

I have CO2 and fert daily. I'm thinking of adding a fixture, or replacing with a 4x fixture for two reasons. 
1) to get greater spread between bulbs as the 2 bulbs close together don't distribute the light very well. many plants, or parts of plants are in shadows even though they should have good exposure. This might be more important than intensity and the greater cause of legginess.
2) just to see what a short burst of extra light will do for plant appearance and color. Getting god light into those areas that are partially obstructed is the benefit I want to see from 4x bulbs, not just more overall light. 

My expectation is, based solely on observation of my tank to date, is that the 4x bulb fixture will provide greater coverage of the tank when running 2x bulbs and a short 4x burst will get even more light into dark areas. I'm hoping that will reduce legginess and produce more uniform color onsome plants.

YMMV.


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## whitetiprs (Aug 28, 2009)

thanks for the responses. I think I will go with a 4 bulb setup, now I just have to decide which one to buy, any suggestions?


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## Nue (Dec 27, 2009)

this would be perfect for you.

http://www.catalinaaquarium.com/product_info.php?cPath=71_136&products_id=1638


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## NJAquaBarren (Sep 16, 2009)

If spread is part of the goal as it is with me, then look for fixtures with max depth. Two that do this are the aquaticlife and Finnex fixtures with LEDs. They have the LEDs running down a ridge in the middle of the fixture, 2 bulbs on either side.

The aquaticlife has built in timers that enable just one plug in your outlet while allowing control of 2 banks of tubes and LEDs independantly.

The Finnex has more powerful LEDs that are dimmable so you can use them as moonlights and for a little shimmer. Great for reef tanks. Certainly not necessary for us. The finned is the more expensive.

The Catalina has a great reputation here. Not quite as much spread as these two though. Buy either with confidence.


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## gpodio (Mar 16, 2010)

Nue said:


> You could probably get away with what you have. T5 WPG rules isn't very good. I use 2x54w t5 on a 55g, and thats still to much. Im having to drop down to 6 hours a day to avoid algae.


It's not as far off as many make it out to be... T5's are more efficient and put out a little more lumens per watt consumed, but I don't feel the WPG rule is much less accurate with T5's as it has always been with CF's and other fluorescent bulbs. Over the years fluorescent technology has progressed at a pretty steady pace, the same things were said when T8's took over T12's and later CF's... each one added to the total lumens we got per watt consumed. If you keep that in mind, you can still use the WPG rule to get a good approximation. It's still the only value readily available for all bulbs...

We don't know if the existing fixture is 2x54W (HO) or 2x28W (NO)... My low light 90g has 3x32W T8 on it and performs well if you choose your plants correctly. 2x54W on a 55g should be manageable however, it's a nice amount of light actually, I wouldn't consider it too much personally.

I like the 4x54W burst in the middle of a 2x54W photoperiod, it will provide you with a lot of flexibility, both in photoperiod and bulb choices.

Regards
Giancarlo Podio


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## Nue (Dec 27, 2009)

So your saying the WPG still applies to T5?


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## whitetiprs (Aug 28, 2009)

I like the catalina fixtures and best of all their prices are alot lower then the "name brand" guys, plus you can pick which bulbs you get. I think I will be going with one of their 4 bulb fixtures. Thanks for the recomendations.


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## Nue (Dec 27, 2009)

whitetiprs said:


> I like the catalina fixtures and best of all their prices are alot lower then the "name brand" guys, plus you can pick which bulbs you get. I think I will be going with one of their 4 bulb fixtures. Thanks for the recomendations.


Your welcome. They are highly recommend on this site. I plan on buying that one when i upgrade to 120g


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## gpodio (Mar 16, 2010)

Nue said:


> So your saying the WPG still applies to T5?


Yes of course it does, you just need to specify that it is T5 your dealing with. Think of it like 2WPG of T5 may be similar to say 2.5WPG of T8...

If you look at the specs of a T5 setup, the numbers are not revolutionary... here's an example:

1. 48" 32W T8 = 2950lumen / 92lpw
2. 48" 28W T5NO = 2900lumen / 104lpw
3. 48" 54W T5HO = 5000lumen / 93lpw
4. 48" 84W T5VHO = 7200lumen / 85lpw
5. 21" 55W CF = 4800lumen / 87lpw

The first three are the same bulb in different diameters and power rating. The last two are from different manufacturers. As you can see, the amount of lumens per watt hasn't changed a huge amount. These are obviously not taking into consideration reflector efficiency, something that we need to keep in mind as the slimmer T5 tubes have the advantage here as well. Also, these values are "ideal" values based on ideal operating temperature, another consideration that is often ignored... T5's emit their peak at 95F compared to 77F of T8 and T12 tubes. This is potentially another plus for the T5 bulb as most fixtures run pretty hot. A 30F shift from the ideal operating temperature causes a 20% loss in lumen output for example...

Many factors to consider, but I do believe the WPG rule is just as "bad" today as it ever was  I recall the same kind of thing was said when CF's first came out, but we all got used to working with CF WPG and before you knew it so few were using T12 lamps that today one would just assume we were talking CF or at least T8 when discussing WPGs.

PS. In the reef forums we usually specify WPG MH or WPG T5 and so on... the two perform differently, but as long as you know what kind of lighting you're working with it's still an easy way to discuss "quantity" of light over a tank.

Regards
Giancarlo Podio


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## captain_bu (Oct 20, 2007)

whitetiprs said:


> I like the catalina fixtures and best of all their prices are alot lower then the "name brand" guys, plus you can pick which bulbs you get. I think I will be going with one of their 4 bulb fixtures. Thanks for the recomendations.


If your tank is deep front to back ask them about making you a custom fixture when you call to order (definitely call for the best deal). The price to select a wider fixture housing is nominal and you can have them space the bulbs for more spread. They will also arrange the banks of bulbs any way you chose for no additional cost if you don't like the stock configuration.


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## whitetiprs (Aug 28, 2009)

The tank is a standard 90 gal. so it is ~18'' front to back. The fixture I am looking at is only 8.5'' wide so maybe a 10''or 12'' fixture with the 4 bulbs spaced alittle farther apart would work. Any suggestions about that?


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## TheRac25 (Nov 5, 2008)

im running 3x t5ho over a 75 raised 28 inches off the bottom and acording to this im right in the middle of high light! be careful with a 4 light fixture! http://www.plantedtank.net/forums/lighting/97622-par-data-selecting-t5ho-light.html maybe even higher with icecap reflectors and runing 65 watts per bulb


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