PAR vs Distance, T5, T12, PC - New Chart

[S&KGray]

Originally Posted by madhatter4

So assuming 1 T8NO@20" gives ~10par, 1 T8ODNO 2X would yield ~20par. If I also assume that 1 T5NO gives about half the par of T5HO, I would get ~30par@20" for T5NO.

The T5NO would yield ~10par more over the T8ODNO, that's not a lot but it gets onto the low light range(barley) for 20" depth.

Does this sound right?

If 1 T8NO@20" is ~10par, 1 T8ODNO 2x would yield ~15par, 3x would yield ~17.5par, 4x would yield ~20par

[Oreo]

What's the conversion factor from LUX to PAR? I understand it would't be exact because of what PAR and LUX are and that different bulbs perform differently throughout the spectrum. Still, it would be useful information to have a ball-park idea of how the two compare from an average bulb.

[madhatter4]

Originally Posted by S&KGray

If 1 T8NO@20" is ~10par, 1 T8ODNO 2x would yield ~15par, 3x would yield ~17.5par, 4x would yield ~20par

Haha... that's embarrassing , thanks for the correction. not sure why I did that.

So that would put a T5NO at about twice the intensity of a 2XOD T8. That's enough to warrant an upgrade I think.

[Hoppy]

Originally Posted by Oreo

What's the conversion factor from LUX to PAR? I understand it would't be exact because of what PAR and LUX are and that different bulbs perform differently throughout the spectrum. Still, it would be useful information to have a ball-park idea of how the two compare from an average bulb.

I haven't tried to determine the answer to that. Most bulb manufacturers don't print the LUX @ X inches rating on their bulb packages, so I never felt it was an important thing to know. I do know that the conversion factor would be much different for a GE9325K bulb, a 6500K cool white bulb, a 10,000K bulb, etc. How much different I don't know either. Someone else can have the fun of figuring this out

T5NO lights are interesting. I read a few years ago that the efficiency for converting watts to light for a T5NO bulb is higher than for a T5HO bulb. And, I know that for any given length bulb, T5NO bulbs are a little more than half the wattage of T5HO bulbs. From that you could assume that a 2 bulb fixture with T5NO bulbs would produce about the same or a little more PAR than a one bulb T5HO fixture. Except, that few T5NO fixtures use reflectors that are nearly as good as typical T5HO fixtures. And, the reflector accounts for a big percentage of the efficiency of T5 bulbs. Until someone gets several PAR meter reading for a few different T5NO fixtures I don't know how we will ever know how to judge those fixtures.

[fishyjoe24]

tom and hoppy where do you think my 192w (2x96w) power compact bulbs stand in the line of par now that they are over 2-20H tanks with the lights beening 18-20 from the substrate, oh and I also have c02 now just need to get the bottle filled and recert.

[madhatter4]

Originally Posted by Hoppy

T5NO lights are interesting. I read a few years ago that the efficiency for converting watts to light for a T5NO bulb is higher than for a T5HO bulb. And, I know that for any given length bulb, T5NO bulbs are a little more than half the wattage of T5HO bulbs. From that you could assume that a 2 bulb fixture with T5NO bulbs would produce about the same or a little more PAR than a one bulb T5HO fixture. Except, that few T5NO fixtures use reflectors that are nearly as good as typical T5HO fixtures. And, the reflector accounts for a big percentage of the efficiency of T5 bulbs. Until someone gets several PAR meter reading for a few different T5NO fixtures I don't know how we will ever know how to judge those fixtures.

As far as reflectors go, a single bulb icecap reflector is no different on a T5HO then a T5NO right? Any upgrading I do will be a retrofit into my hood rather then a T5NO fixture.

[Minsc]

Looking at a Coralife T5NO 2 bulb fixture, it looks as if maybe a third of the light being produced by each bulb is making it into the tank. The reflector design is just that bad.

So, it would probably take 2-3 fixtures, of 2 bulbs each, to equal the light from a single T5HO with a quality reflector.

[Hoppy]

Originally Posted by fishyjoe24

tom and hoppy where do you think my 192w (2x96w) power compact bulbs stand in the line of par now that they are over 2-20H tanks with the lights beening 18-20 from the substrate, oh and I also have c02 now just need to get the bottle filled and recert.

Those tanks are 24 inches long, right? And, they are end to end, or 48 inches total length? With a pair of 35 inch long lights sitting on the top of the tanks? Assuming that is all correct, the half of each tank directly under the pair of bulbs, which have to be close together, given the 12 inch depth of the tanks, would be about twice what one bulb would give.

The big unknown is whether these are like AH Supply light kits, or like Coralife light fixtures. If like AH Supply, the PAR would be around 100 micromols of PAR, but if like Coralife, it would be more like 40 micromols of PAR. At the end of each tank not directly under the bulbs, the intensity would be quite a bit less.

[Oreo]

Anybody here feel like lending / renting me a PAR meter? If so I'll take readings of a 10,000k T5HO and a 6700k T5HO at various heights in both PAR and in LUX and post the results. (Such a simple thing but no one has done this yet.)

[Hoppy]

I just edited the chart here, http://www.plantedtank.net/forums/li...ml#post1093075 to add a table that might make it easier to use.

[barbarossa4122]

Hi,

According to your chart I have high light. Thanks for the info Hoppy.

[Nate McFin]

Why is this not a sticky yet???

[reybie]

Thanks to the charts I can now confirm that I was sunburning my plants and fish

I shut down 2 of the T5HOs and will continue with just 2 now and those alone would give me ~100 micromols at my current height of 23" from substrate.

[ballen]

Ok im newer to planted tanks and trying to learn as much as i can as i slowly build up my 75g tanks. Right now i am trying to figgure out my lighting needs. So here is my question with only being able to get t5no lights at 2x28watts how many would i need to buy to put me at the higher end low to low mid mid light range if my substrate will be at about 20 to 22in from my light with basic reflection ie white paint as the min but more likly Aluminium coil stock lind custom hood. I know that i should try for a better light scorce but because of where i live and cash flow it has limited me in what i can buy at this time.

[S&KGray]

You should be fine with one 2x28 per tank to get low to med light

Edit: i meant with a good reflector, see Hoppy's comments below