Lighting: T5 vs Metal Halide???

[Canadian]

Originally Posted by StirCrazy

PAR meters are calabrated for either sun light or electric light, and at a base spectrum. the longer wave lenght of the blue light in an actinic bulb is way out of perportion for either calabration as they are done based on 5500K(if I remember corectly). so when it recives a higher level of actinic than the calabration set had it thinks it is more powerfull and reads acordingly. the same holds true for say 3000k, it will report less PAR than there actualy is.

they pick the middle for the calabration and then it is only out a bit on the ends so you get a happy medium. I think at 400nm mine is 2.7% higher than actual ouput. so it isn't a lot, some meters are scewed by as much as 10%.

this is why I don't like to compare different colors of lights with out a disclamer, for an example, my AB 10K 250watt SE driven by a M80 ballast and my special home made reflector, would put about 550 to 600 units of PAR on the bottom of my 24" deep tank, so that is through 22" of water and 7" of air (I don't run the water 2" below the top, only 1 but my sensor is 1" tall also) for a total distance of 29" A tek unit with a 10K bulb load (4 bulbs) placed directly on the top of the tank for a distance of 24" from the sensor (22"water 2" air) got a max reading of 295 units of PAR. Still a respectable amount of light. now as for the disclamer, a 10K ab is actualy 12600ishK so a bit more actinic than the 10K T5s. so lets use the 10% which is the worst I have heard of and take that off my ABs it would still come to 495 to 540 Units, but seeing as there is only a 2000K difference in the bulbs I would guess it would be a lot close to the actual reading, as it takes some good actinic, as in 20K bulbs or pure actinic bulbs to get the meter to over estamate.

Steve

If that was the case wouldn't you expect an actinic T5 lamp to produce greater PAR values than a "whiter" lamp - given that you're suggesting 420nm wavelength is some how misinterpreted as being more "powerful"?

Here are measured PAR values for various T5 lamps:

http://tfivetesting.googlepages.com/par

[Canadian]

Steve,

Can you please explain how actinics produce "false high" PAR readings despite the fact that measured PAR values for actinic T5HO lamps are considerably lower than whiter lights?

For example:

ATI
Sun Pro 357
Aquablue 336
Blue Plus 311
Actinic 137

How does that actinic lamp running at 137 PAR some how artificially create "false high" PAR readings when the measured PAR is less than other lamps surrounding it?

[StirCrazy]

Originally Posted by Canadian

Steve,

Can you please explain how actinics produce "false high" PAR readings despite the fact that measured PAR values for actinic T5HO lamps are considerably lower than whiter lights?

For example:

ATI
Sun Pro 357
Aquablue 336
Blue Plus 311
Actinic 137

How does that actinic lamp running at 137 PAR some how artificially create "false high" PAR readings when the measured PAR is less than other lamps surrounding it?

dimmer bulb, who knows how they are made. anyways I am trying to get my house painted so I can sell it so I don't have time to explain it again.. Go to APogee's site they tell you what there corection factors are and such. wanna buy a house?

Steve

[StirCrazy]

Ok, re read my stuff, between painting rooms.. I made a mistake, yes I know.. imigian that, not that it happens a lot but yes even I can make a mistake.

the meters do not over estamate actinic, the under estimate actinic and overestimate the higher end. in a rounded out bulb this will all work out in the pudding (6500K ish) but in a actinic bulb it will give you a lower reeding than you should have and in a 3000K bulb it will give you a higher reeding than you should have.

reasons are due to the spectral responce of the meters to the wave lengths, and to get a unit that reeds good all over you need to spend over 1000.00 bucks.

anyways sorry if there was any confusion Mr Canadian.

Steve

[Canadian]

Thanks for the correction Steve. That makes a lot more sense now.

[StirCrazy]

Originally Posted by Canadian

Thanks for the correction Steve. That makes a lot more sense now.

no problem, I was painting and something was striking me as funny about it.. so when I finnished painting the laundry room I took a short break and check my referance and found there error. then I went and painted one of the kids bedrooms, but on the good side, if this last coat coveres good, then tomorrow I have to do some trim and I am done painting my house

Steve

[Canadian]

Originally Posted by StirCrazy

no problem, I was painting and something was striking me as funny about it.. so when I finnished painting the laundry room I took a short break and check my referance and found there error. then I went and painted one of the kids bedrooms, but on the good side, if this last coat coveres good, then tomorrow I have to do some trim and I am done painting my house

Steve

Are you still planning on moving to Kamloops Steve?

[Myka]

Originally Posted by StirCrazy

no problem, I was painting and something was striking me as funny about it..

I do this too...except usually when I'm trying to sleep, and I'm haunted by reef questions. Or what my next upgrade should be...