Lighting Upgrade Question

[Dana Riddle]

One other comment, if you decide to use lenses, make sure you can easily replace them as the 400nm LEDs will cause 'fogging' (yellowing) of them after a while.

 

[sbash]

One other comment, if you decide to use lenses, make sure you can easily replace them as the 400nm LEDs will cause 'fogging' (yellowing) of them after a while.

Interesting, I did not know that!

 

[ArialReef]

Haha, windex look...

That's a good place to start, grab a couple extras so you can swap some around in case you want to play with the look... But yeah, that should make the corals pop and not be totally blue (might be a bit purple though)...

As for lenses, I wouldn't use lenses. Usually lenses restrict the spread down to 90 or 45 degress, while most LEDs naturally have a 120-140 degree spread. But if you are getting a lot of spillage out the sides, it may be a good idea to add lenses.

Okay, so no lenses. My question is how do I make the fixture waterproof?

 

[sbash]

Okay, so no lenses. My question is how do I make the fixture waterproof?

Make sure you pick a chassis with a plastic cover...

 

[ArialReef]

Make sure you pick a chassis with a plastic cover...

What kind of plastic cover should I be looking for so it doesn't obstruct the LEDs and/or reduce the amount of light that goes in the tank?

 

[Dana Riddle]

Most plastics have a cutoff at about 400nm, so UV transmission suffers (this is the reason plastics yellow and eventually become brittle when exposed to UV.) Low iron glass is a better option for UV.

 

[ArialReef]

Most plastics have a cutoff at about 400nm, so UV transmission suffers (this is the reason plastics yellow and eventually become brittle when exposed to UV.) Low iron glass is a better option for UV.

Okay, thanks! Any other suggestions before I go shopping for LEDs and stuff?

 

[ArialReef]

Alright then! I'll update when I have it!

 

[ArialReef]

So, uh... It would seem that my local led shop doesn't have any 395-400nm LEDs in stock, the closest ones are 385nm and 420nm. There are some available online but I don't think I can get those in time. What should I do?

 

[sbash]

So, uh... It would seem that my local led shop doesn't have any 395-400nm LEDs in stock, the closest ones are 385nm and 420nm. There are some available online but I don't think I can get those in time. What should I do?

Unless Dana thinks 385nm is usefull, I would order them online; I base most of my LED fixture building off his publications and as far as I can tell lower than 395 is ideal. That said, you could probably get the store to get them in, build your fixture with 420s and 450s and just swap a couple out when they become in stock again...

 

[Dana Riddle]

385nm is OK, it's close to the 365nm mercury line spectrum seen in all lamps that contain mercury (all fluorescents, metal halide, mercury vapor.) There will be some spillover into the visible range - a deliberate effort to comfort those who would think the LED has burned out if they can't see the UV output. There is good evidence that UV in this range is photosynthetically active, plus it will make *some* corals fluoresce (if they're able to do so.) I just received some custom-built LED arrays that produce narrow bandwidths and hope to do some experiments with them after I get the speaking engagements out of the way.

 

[ArialReef]

385nm is OK, it's close to the 365nm mercury line spectrum seen in all lamps that contain mercury (all fluorescents, metal halide, mercury vapor.) There will be some spillover into the visible range - a deliberate effort to comfort those who would think the LED has burned out if they can't see the UV output. There is good evidence that UV in this range is photosynthetically active, plus it will make *some* corals fluoresce (if they're able to do so.) I just received some custom-built LED arrays that produce narrow bandwidths and hope to do some experiments with them after I get the speaking engagements out of the way.

So maybe I should go with 2 10.000K whites, 3 385nm UVs, 3 420nm Blues, and 8 450nm Blues to balance things out or should I go with 6 385 nm/420 nm? Which one?

 

[Dana Riddle]

If the choice is between 385nm and 420nm, I personally would go for the 420nm. Most of their output can be measured with a PAR meter, absorption is outside (kind of) that of xanthophylls, and so on. Still, that's a lot of blue.

 

[ArialReef]

If the choice is between 385nm and 420nm, I personally would go for the 420nm. Most of their output can be measured with a PAR meter, absorption is outside (kind of) that of xanthophylls, and so on. Still, that's a lot of blue.

Closest one I could find online is a 3W 390-410nm LED. Should I go with it?

 

[Dana Riddle]

Sure, that will work photosynthetically-speaking. Still, it's a lot of blue overall.

 

[ArialReef]

Sure, that will work photosynthetically-speaking. Still, it's a lot of blue overall.

Maybe 4 whites 6 400nm 6 450nm ? I like it blue tho... I want maximum growth and I do not care if it'll hurt my eyes haha...

 

[Dana Riddle]

Go for it!

 

[oreo54]

If the choice is between 385nm and 420nm, I personally would go for the 420nm. Most of their output can be measured with a PAR meter, absorption is outside (kind of) that of xanthophylls, and so on. Still, that's a lot of blue.

I'm confused?

In acetone so not in real life..

 

[Dana Riddle]

The 420nm output is away from the maximum absorption of those xanthophylls found in zooxanthellae (diadinoxanthin and diatoxanthin) - more so than the output of a LED emitting a maximum at 450nm. *Most* quantum meters don't see radiation below 400nm, although I've seen one device from Europe that could measure into the UV-A range.

I'm confused?

In acetone so not in real life..

 

[ArialReef]

I ended up with 10 LEDs. 2 10.000K Whites, 4 455nm Blues, and 4 400nm UVs. All three watts. I didn't put 16 on it because of overheating, heck even 10 LEDs is still very hot. I'm planning to put a few fans in there to keep temp controlled. Whaddya think?