2X24 watt T5 Par

[choss]

I have not seen a lot published on the par of shorter T5 bulbs. I'm debating retrofitting a few 2X24" Giesemann Spectra fixtures in a hood and am wondering whether they will provide adequate light for a shallow frag tank. Does length and wattage matter I guess is the main question.

Interested in hearing any opinions or experience in measuring par on shorter fixtures.

 

[mcgyvr]

The par should be roughly equivalent to a longer bulb its just not spread out over the same distance.

And yes it should be just fine for any frag tank..

 

[oreo57]

I have not seen a lot published on the par of shorter T5 bulbs. I'm debating retrofitting a few 2X24" Giesemann Spectra fixtures in a hood and am wondering whether they will provide adequate light for a shallow frag tank. Does length and wattage matter I guess is the main question.

Interested in hearing any opinions or experience in measuring par on shorter fixtures.

Example.. use the scale not the "color"..

In this example you lose at least 25% (roughly) overall for a 24" vs 30"..4 tube lights
Of course you still have reflectors, ballasts, tubes to consider.....

 

[rtparty]

Example.. use the scale not the "color"..

In this example you lose at least 25% (roughly) overall for a 24" vs 30"..4 tube lights
Of course you still have reflectors, ballasts, tubes to consider.....

Which company's info is that?

I've tested a lot of stuff and have never seen that. Not even close either. If you get 24, 36, 48 and 60" bulbs and test them, PAR will usually be within 10%. That falls in line with error of the PAR meter plus slight differences from bulb to bulb.

More wattage does NOT equal more PAR with T5s. At least not in the case of 24w for 24" bulb compared to 39w for the 36" bulb. Now take a 24" bulb and overdrive it to 40w and you'll see a 10-15% increase in PAR. You'll also kill bulb life in doing so.

Most of my testing has actually shown that 36" T5 bulbs are the worst performance wise. 60" bulbs tend to have slightly more PAR per watt but it's negligible.

Edit: If you look closely, the 24" fixture didn't quite hit 100 PAR. The 30" fixture doesn't hit 100 either...

 

[choss]

The par should be roughly equivalent to a longer bulb its just not spread out over the same distance.

And yes it should be just fine for any frag tank..

Thanks for the input! Much appreciated