t5 vs MH

[StirCrazy]

Originally Posted by Rikko

I should mention that presently, lumens/watt output is still the greatest with MH/HQI..

don't get caught up with the lumens per watt thing or even lumins for that matter. the big difference is the actualy intensity of the light sourse which allows it to punch more light deeper into the water.

a good example here is with my two 96 watt PC's and two 95 watt VHO's I got an average PAR reading of 280 at a depth of 12"(7 of that water) so that is with 382 watts of light. One SA SE 250 watt bulb on a HQI ballast give me a reading just shy of 900 at the same depth, with only 250 watts of light output. so the intensity of the point sourse type light far exceded that of the gas tube type.

Steve

[Invigor]

steve for mythbusters canadian edition!

[Funky_Fish14]

Yeah but steve....the MH will give a much lower PAR rating off to the side of the tank than it would directly below the bulb. Take a reading to a side of your MH and not pointing at it...

Also, you said that the T5 Is just more heat in a smaller bulb but they emit LESS heat, thats what they were designed to do, emit more light and less heat than a startard T12. Also, that coloration you are talking about isnt necessarily all actinic. Who says everyone has 4 actinic and 2 daylight bulbs? I dont know if you read my post, but like I said, some people on RC switched to T5 lights from MH on 24" deep tanks and some of the corals that used to be at bottom were getting too much light and did better shaded under the T5s.

Also, these guys went to lower wattages of T5 compared to what they had in MH.

Yeah the T5 wont give the shimmer.

Also, T5 NO's from what I have heard and seen from everyone are crap...plain and simple. And T5 are useless(well not uselesss, but much more light is directed into the tank) without SLR(Single Lamp Reflectors).

Chris

[Funky_Fish14]

O yeah Steve,

"of the gas tube type"

MH bulbs also have a gas chamber where the light is emitted from. They dont have a filament.

Chris

[StirCrazy]

Originally Posted by Funky_Fish14

O yeah Steve,

"of the gas tube type"

MH bulbs also have a gas chamber where the light is emitted from. They dont have a filament.

Chris

your being silly here, I coulden't remember how to spell floressent at the time. and there is a difference becaue a floressent is a gas tube that emits light by exciting the gasses to the point where they emit light, a MH or HID actualy uses a broken filiment and causes a "sustained" spark to jump across the two filiments and create the light output.

Originally Posted by Funky_Fish14

Yeah but steve....the MH will give a much lower PAR rating off to the side of the tank than it would directly below the bulb. Take a reading to a side of your MH and not pointing at it...
Chris

oh ya but ya but, bull malarkie is the best reply for that one you will have the exact drop in intensity off to the side as you would with a floressent tube. (you do know that light radiates at all angles from a MH bulb right?) at anyrate the only drop off by moving to the side is due to an increas in distance (which isn't much) and if you are not holding the measuring insturment corectly (as in keeping it strait up and down when moving to the side) for a proper reading the measuring insturment must alway face the bulb no matter where it is in the tank, so as you move to the side you angle the measuring insterment acordingly. any other variance in intensity from the bottom middle of the tank to the bottom edge is due to pour reflector design or to small of a reflector, and this is the down fall of using a DE type bulb as the smaller reflector makes for a focused light patteren.

Having said that a reflector set up on a floressent T5 bulb can have the same effect by limiting the light out to the sides so with any type of lighting you have to realy look at the reflector design.

even if you have a bad reflector design that does limit the bottom edges of the tank in PAR out put, whoulden't that now be a perfect place to put your low light corals?

Steve

[Funky_Fish14]

Yes steve you are correct about the MH. I wasnt thinking about that when I said It, I was just thinking about the fact that the chamber in a MH bulb where the arc occurs is filled with a special gas.

I know that light radiate from all sides, ofcourse! Lol. Its like the sun in a box, hehe. However here is a dilema, your corals are not getting light from above as they would be with T5, and then there is the possibility of them being shaded from the light(but this is a pretty crappy arguement as you said you could put lower light corals there), but Also you need more bulbs and higher wattage/power comsumption to cover the same area as you would with T5.

Having said that a reflector set up on a floressent T5 bulb can have the same effect by limiting the light out to the sides

This is where I think you are wrong. A T5 bulb setup should span the length of the tank...no? So why should this limit the light on the sides? It should have the same intensity as that in the middle of the tank(well, the PAR readings should be the same, though the center of the tank may be ever so slightly brighter because of the light from the ends of the bulb some of it would spill to the center of the tank from both sides but on the ends it would only spill from the center and not from the other sides of the tank but this is such a minute difference and its beside the point, lol).

I have a question about PAR(PP something something....photosynthetic photon something something, lol). How does it relate to the intensity of the bulb? I mean, can you have a bulb that would be as bright as say a 400W halide, with 0 PAR? I know the ballast can affect it(ie: a 250W 10K XM MH bulb running off a standard PFO ballast has 800 and a few, whereas running of an HQI ballast, the PAR goes up by over a hundred). I havent done much reading about it. And also, am I correct to say that the reason trilinearmipmap had bad growth of his Monti frags was because though T5 may be very bright, and the PAR may be relatively high, each segment of the light does not have a very high ouput when compared to a segment the same length of a MH so therefore it cannot send that PAR intensity far enough down, though the bottom of the tank may still be very bright? That might explain what I was talking about earlier with those guys having too much light at the bottom of 24" deep tanks. I dont know how their growth was though? Maybe its that yes, they are bright bulbs and produce alot of light, but that light is not strong enough to push the PAR down?

Sorry bout the really long post. Thanks.

Chris

[Funky_Fish14]

Bump.