Flood light wattage.

[aravind90chan]

Hi,
I am planning a low tech, shallow planted tank with a few emersed and submerged plants (umbrella palm, ludwigia etc).
I plan to go with LED flood lights for the tank.
Should I pick 30W or 15W Flood light?
I plan to hang about a feet+ above the rim of the tank.
Tank dimensions are 24"x24"x12".
Thanks.

[JLW]

The PAR on various LED flood lights is really variable, so it's hard to answer that effectively.

[DonkeyFish]

What Josh said.

To be at least somewhat helpful in a response though, LOL, *I* might suggest going with the 30W and you could always hang it higher if it's too much light?

[aravind90chan]

Thanks a lot.

[Tim_Koles]

Trying out a flood light setup at the moment on an open air tank. I tried a LED grow bulb I got on online but the color temp was way too blue for my liking. Plants grew but not great. Switched it out a few weeks ago for one I got at HD. A Sylvania Night Chaser LED. 40 degree, 250watt. It does not give the Kelvin value but its a much nicer daylight look. 2650 lumens. Very bright. I have not tried out the PAR meter in it but will do so at some point. Plants are still not doing what I want but I need to give them some time with the new bulb. I've been very sick the last month and haven done much with my tanks so that doesn't help either.

PS 250 watt is the standard rating, supposedly this uses 25 watts actually. Light is brighter than some others I tried that used more power

[Wobblebonk]

lumens (eye brightness) per W does not really indicate more PPF/watt, and many of the meters are not great at seeing violet or deep red light either.

The night chaser is either 3000K or 5000K low 80s cri. http://assets2.sylvania.com/media/bin/a ... et-1378033
I suppose if one is looking at flood lights they're probably trying to be cheap but the brightness/lumens are deceptive. A low cri high efficacy (Lumens/watt) light is likely dominated with mostly green or yellow light which the eye just sees better... (lumens are weighted towards the eyes so like a lime green led made with a royal blue + green phosphors is much higher lumen than just a royal blue led but not more par.) The weighting of lumens is nearly the opposite of PUR, so the eye doesn't see violet well, blue and red it sees kinda okay... but it sees yellow and green very well, and chlorophyl sees violet/blue/red very well and yellow/green okayish.

They don't show spectral data (sylvania) but I like https://www.stockholmlighting.com/prodf ... w-7282.pdf these except they no longer make the vivid 4000k or 5000k bulbs so it's kind of steep per bulb . But in there with the "brilliant" series 85ish cri bulbs you can see how it's mostly yellow light (these are a little off because they're all violet pump leds instead of royal blue which the sylvanias undoubtedly are) with a terrible r9 (red) value. Lumens per /w will never match the sylvanias because blue is higher lumen than purple and yellow higher than red but lifespan is longer/ better heatsink lower watts, V+RGB phosphors is a much prettier / higher PUR white than RB+Y phosphor imo.

[aravind90chan]

@Tim_Koles. Hope you get better soon.
@Wobblebonk. Thanks for the detailed reply. If that is the case, should I look fot T5 HO lights instead? Since there are too many options, it is a bit confusing.

[aravind90chan]

https://store.waveformlighting.com/prod ... 1573147750
What are your thoughts on this?

[aravind90chan]

Not sure what kind of fixture to use to elegantly mount it.

[aravind90chan]

https://www.waveformlighting.com/photom ... 005.65.pdf
This is the spectrum data.