LED: How to know if UV is too low?

[secure1347]

I have a 150 gallon running mostly softies, and some LPS and only a couple of SPS and was wondering if my UV settings might be too low on my Hydra 52's. I have seen a lot of people use more UV and I'd like know how to tell if it would benefit me to up the UV. I realize that might not be an easy answer and perhaps I should slowly increase it over a long time period to see if it promotes more Coral growth and doesn't bleach them, but wanted to see if there were any other suggestions.

Here's a snapshot from my Director showing what the peak values are on the left side. Thanks for any help.

http://www.reefcentral.com/forums/picture.php?albumid=9484&pictureid=76579

[GimpyFin]

I run the UV between 80 and 90 on mine with no issues. The UV LEDs on these are 400 nm, so it's almost a stretch calling them UV to begin with. IMO, I wouldn't worry much about running them higher and damaging something. They're also 1 LED per puck and don't use much of the power on the light compared to the whites and blues. (IME, You're more likely to have bleaching from running the whites and blues too high as they use the most power.) Anyway, just my $.02. Hope that helps.

[secure1347]

Hmm that's interesting, but could also be a good reason why there is so much discrepancy between what people run them at. Some people run them at ~30% and some run them at %80+ which I found surprising. There is much more consistency with the values of the other colors it appears.

[Ron Reefman]

Hmm that's interesting, but could also be a good reason why there is so much discrepancy between what people run them at. Some people run them at ~30% and some run them at %80+ which I found surprising. There is much more consistency with the values of the other colors it appears.

That's because the violet (400nm is NOT UV) end of the spectrum is much less important to the health of the coral and more about how the colors pop with or without the violet.

[2smokes]

Leds dont have UV,its just pink or blue color leds marketed as ,,UV,,.You could go at maximum power with them because that ,,UV,, cant roast your corals.Or you could go a bit less than maximum power to protect the led diodes so they will last longer.Only light that have the UV spectrum are the ones that use bulbs made of glass ,like T5 and MH.Leds lenses are made of plastic and that would get damaged if they were emmiting real UV.

[Optionman]

I've been running 4 Hydra AI 26 lights above my 150 gal Red Sea S650 for approximately 5 months after running 10 T-5 lights during the tank's first 2 months. I run almost exclusively the blue/violet/purple and UV and have the green/red/white off (i run the white maybe 1 day/week to appease my wife). I slowly increased the intensity level over the first several months and now run the blue/violet/purple at 110% and the UV at 60%. The lights run for 12 hours with 2 hour ramp-up and ramp-down.

I have no algae problems and my coral growth has been crazy.

[Wazzel]

In most cases the manufacturers have already taken into account the color mix. That is why things like UV, violent, red and green are fewer lower powered diodes. When run at the same level as the blue channel there contribution is small already. There is no reason what-so-ever to run them significantly lower than blue.

[Wazzel]

Leds dont have UV,its just pink or blue color leds marketed as ,,UV,,.You could go at maximum power with them because that ,,UV,, cant roast your corals.Or you could go a bit less than maximum power to protect the led diodes so they will last longer.Only light that have the UV spectrum are the ones that use bulbs made of glass ,like T5 and MH.Leds lenses are made of plastic and that would get damaged if they were emmiting real UV.

It is very violet, not UV. From what I have seen on spec sheets the very violet diodes just touch the range that would be considered true UV. The name is slightly misleading.

[blasterman789]

Given the fact most of us have our higher powered LED rigs turned down, and our eyes are significantly less responsive to 400nm light than 455nm light, the only thing 400nm diodes accomplish is making our tanks look dimmer per relative PAR level.

Long before LEDs entered the scene along with violet 400nm I don't know of any reefers who claimed 420nm fluorescent actinic was required for coral growth.

[Ron Reefman]

Long before LEDs entered the scene along with violet 400nm I don't know of any reefers who claimed 420nm fluorescent actinic was required for coral growth.

Is 400nm to 420nm spectrum required? Probably not.

Does it have an effect? Probably promotes some of the fluorescence that coral pigments produce making some of them look... better, different, cooler... pick your adjective.

[secure1347]

All great info thanks a lot. I think I'm going to change things up a little bit on my lighting profile to make it a little more blue and maybe lowered my red and even my green. Even though I have 0 phosphates I get a lot of algae growth on the glass so I'm wondering if the Red/Green is helping to contribute to that.

Also my Montipora Cap is directly under the light and it's not as deep red as I think it should be so maybe I've got the white intensity up a little too high.

[Wazzel]

Here is a chart I put together for a single Hydra52. I tested all the channels individually and them all together. Hope it helps.

https://photos.smugmug.com/Other-2/Hydra52-Par-Study-28-Dec-14/i-tVZd5Fv/0/L/hydra52%20par-L.jpg

[secure1347]

Wazzel,

Thanks very much this could be helpful, but I want to make sure to understand it...

How are you getting the overall power level for all colors? Are you using the Director slider for intensity and then just selecting a specific color temp to use?

This wouldn't show me what to use for the different settings though right? Looks like it's just the %'s of each color that contribute to the PAR?


My lights are a little higher (I think ~12 inches), but I imagine this is still fairly close. I've got two of them on each side of my 150 gallon so I imagine that will bring the PAR level back up slightly to make it close to your data from a single unit.

[Wazzel]

Wazzel,

Thanks very much this could be helpful, but I want to make sure to understand it...

How are you getting the overall power level for all colors? Are you using the Director slider for intensity and then just selecting a specific color temp to use?

This wouldn't show me what to use for the different settings though right? Looks like it's just the %'s of each color that contribute to the PAR?


My lights are a little higher (I think ~12 inches), but I imagine this is still fairly close. I've got two of them on each side of my 150 gallon so I imagine that will bring the PAR level back up slightly to make it close to your data from a single unit.

To get the over all power I set the level for each individual color to the same power. To do the individuals I set all to 0 except for the one I was using.

It will not show you what settings to use. It was done so I could understand the relationship between each color and how the intensity varied with power settings. Since I went through the effort I documented what I did and share it. When I say things like UV, V, G and R do not contribute much to the over all power and turning them down is not necessary, this is where I got the data.

On my 120 the lights are about 12 inches above water. To know what is going on in your tank you should probably get a par meter. I suggest renting or borrowing. It is not an item you use often, as I found out after getting mine.

[secure1347]

Ok thanks that makes much more sense now. so the UV, G, R, and V all contribute very little to the overall PAR and are mostly for color mixing to get your desired color. However, I do realize some of the Corals still need those colors for growth etc.

Yes, I've been seeing how much they cost so I'm going to ask around and see if there is one I can borrow. Hate to spend that much money for a one-time thing.

[Wazzel]

Ok thanks that makes much more sense now. so the UV, G, R, and V all contribute very little to the overall PAR and are mostly for color mixing to get your desired color. However, I do realize some of the Corals still need those colors for growth etc.

Yes, I've been seeing how much they cost so I'm going to ask around and see if there is one I can borrow. Hate to spend that much money for a one-time thing.

Correct, the chance of overdoing any of those four colors is really small as long as you do not have the blue and white channels low and the other wide open. I run everything but white at the same level, white is a bit lower.

If you do not have luck finding a meter local let me know. I rent mine out by the week plus round trip shipping.