# confused with PAR and watts per gallon. am i getting enough light?



## Richbinduga (Apr 4, 2013)

I'm trying to aim for med to high light preferably but when i read watts per gallon rule im short of low light. a couple PAR charts i have read say that im getting medium light and others say i have high light. I'm pretty sure im reading something wrong though. i currently have an aquatic life fixture with 2 t5ho bulbs in it. it looks bright! i know that dont mean anything though lol. im using it for my amazon swords in my 55 gallon. if someone could help me clarify this, thatd be a big help!!


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## Gizmo (Dec 6, 2010)

2 48" T5HO bulbs (I'm assuming 54W) would put you in the medium-high spectrum. What Kelvin rating are the bulbs?

Little things make a difference, like the height of the fixture above the water (varies), the presence/absence of a hood (20% different in light intensity), the cleanliness of the hood (calcium deposits can GREATLY reduce the effectiveness), etc.

Watts per gallon is almost completely useless with T5HO lighting and LED lighting. PAR values can be obtained by a Google search for anyone who has taken the measurements for that fixture (The Planted Tank - Articles, Forums, Pictures, Links is a good resource for PAR), or you could see if somebody like jrman83 would be interested in letting you borrow their PAR meter. I've got a Lux meter, which isn't the best for measuring PAR but you can get a rough estimate. If you're interested, I can loan it to you, but I'd pursue a PAR meter if I were you.


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## Richbinduga (Apr 4, 2013)

what exactly is kelvin rating? i have the two bulbs, one is a roseate bulb, dont really say anything. the other one says 6000K. Is that what you mean by kelvin? the 6000k? the lights are mounted 2 inches above the surface. i do have a glass hood because i do have some jumpers. however, i do clean in regularly


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## Gizmo (Dec 6, 2010)

The roseate is probably 5500K, and you're right, the 6000K is the Kelvin rating. It refers to the black-body radiation rating, but it translates roughly into what frequency/color light the bulb emits. Both are pretty low on the Kelvin scale, and the 5500K is pretty useless in a deep tank like a 55. If I were you, I'd replace the 5500K with an 8000K or 10000K bulb.

For the jumpers, have you thought about light diffuser grating? (egg crate). You can buy it at Home Depot or your local hardware store, and it allows a LOT more light through while preventing jumpers unless they're very small and can fit through the grating.


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## Richbinduga (Apr 4, 2013)

i have thought about the egg crate stuff yeah, but at the same time i dont want my tank to look like crap. im really not sure where to get better bulbs. the ones i have i got offline and they said they were made more the light fixture. could bulbs with more kelvins even work for my fixture?


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## Richbinduga (Apr 4, 2013)

im not sure if they make the same bulbs the same size with a higher kelvin rating


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## coralbandit (Jul 29, 2012)

Kelvin rating has nothing to do with fitting in your fixture.If you have a T5HO 48" then ANY T5HO bulb will work.a 55 is on the deep end so I roll with Gizmo on replacing the roseate(maybe both) bulb/s with 8,000-10,000K.My LEDS are 12,000k for my 180 and I'm medium at best.
1^ with the link to par also ,watts per gallon is like inches of fish per gallon(So 1970's if any of you remember them {besides me!})
The reflector in your fixture makes a big difference also.


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## Richbinduga (Apr 4, 2013)

Where can I get replacement bulbs then? That was really all I found. I was told I needed something that shined a red color because that's what the plants needed


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## Richbinduga (Apr 4, 2013)

Hypothetically, what if I replace the other ho 1000k bulb with a 10000k bulb and keep the roseate? I'm just throwing ideas out there because I heard they need a lamp that glows in the red light spectrum. I don't know though, I'm just saying haha. Lights really never were my thing


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## Gizmo (Dec 6, 2010)

48" 54W 10000K T5HO bulb:
Amazon.com : Aquatic Life 54-Watt 10000K T5 HO Lamp Aquarium Light, 48-Inch : Pet Supplies

Replace your roseate bulb and keep the 6000K bulb.

Red is great for plants, but it doesn't penetrate very deep into the tank (red light attenuates faster). Therefore, your plants really won't benefit from red light unless they're right at the surface.


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## Gizmo (Dec 6, 2010)

Also, as an aside, you have 108 Watts of T5HO over your tank right now, which puts you in a pretty good light range for a 55.


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## jrman83 (Jul 9, 2010)

I would get one of these and then get one of the 10000k bulbs with it. Or, get 2 of the 6500k: CATALINA AQUARIUM 54 WATT 6500K DAYLIGHT WHITE FULL SPECTRUM T5 HO AQUARIUM LIGH

I would say that your light level is well into the medium range. With T5HO it is the quality of the reflector that makes all the difference. Some give an effective rating of up to 4 times the rated wattage. I would think that the fixture you got is probably on the lower end. Regardless, you should have no problem growing most things you will want.


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## lonedove55 (Jan 25, 2012)

I've never used this brand bulb before, but Kensfish.com usually beats everyone else in price ( excluding shipping costs).

Wavepoint Sun Wave T-5 HO Bulb

Wavepoint Tropical Wave T-5 HO Bulb

The Sun Wave 12,000K might be a little too much on the bluish side though. Maybe use one of each?


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## jrman83 (Jul 9, 2010)

Gizmo said:


> Also, as an aside, you have 108 Watts of T5HO over your tank right now, which puts you in a pretty good light range for a 55.


Is this a reference to a WPG formula? Which is useless for T5HO or useless in general?


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