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[Reply #15 on:]

RGB LED's are really not that expensive.  $0.99 each is really not that bad.  http://www.mpja.com/prodinfo.asp?number=17137+OP

[Reply #16 on:]

I don't mind about the cost. I'm wondering about the color. Wondering if anyone has the RGB combo to use.

I'll probably order some today and let you know what I come up with.

[Reply #17 on:]

This is terrific. I keep Vivariums at home (Partial water and partial planted area terrariums, usually for maintaining a population of tree frogs, salamanders or amphibians) and I would love to build an arduino-based system for maintaining moisture and temperature. Right now I have an ultrasonic mister and lights on a timer, but it's crude, and it would be great to have some fans kick on over a certain temp or foggers start below a certain humidity.

[Reply #18 on:]

If you're really interested in learning about lighting I'd highly recommend this site:

http://www.advancedaquarist.com

[Reply #19 on:]

Interesting. I found an article about LED lighting where they break down what colors show up. It looks like 45% blue, 20% red, and 35% green.

I'll be doing some more reading on this site... lots of good info.

Thanks for the link, it's helped a lot.

[Reply #20 on:]

Thanks for all the help everyone. I've ordered a bunch of stuff: ph sensor, temp, float, rgb leds etc.

A big thanks to jener8tionx... the links on your site saved me a bunch on the LCD and the ph sensor as well as show me an outline on what I should get.

I've gotten some plexi which I'm preparing for the LED array (100 rgb, 50 on each half). My thoughts were to use 3 pwm outputs to drive some mosfets (I have some IRF540's 100V 22A, more than is needed I know). Does anyone see any problems or have suggestions to that? The LED's will probably be hooked 2 in a series X 25 in parallel.

I'm going to be documenting the project on my site with pics and videos, links to come when I've actually started.

[Reply #21 on:]

Since LED's are diodes, each with a different specific forward voltage, will hooking them in parallel work? I thought the lowest forward voltage diode would get all the current and expire horribly. That's why I was considering doing my lighting direct from the mains. I'd have a nice high voltage and connect them in series.

[Reply #22 on:]

Thanks for the comments everybody!

[Reply #23 on:]

Hello
I have been thinking about lighting, but for fresh water, the problem I face is which wavelentgh to use:
chlorophyl a has 2 absorption peaks 430nm and 670nm
that's the wawelentgh of the led you should use for max efficiency.
chlorophyl b 475nm 630nm
The biology question is which is optimum for your tank (guess it depends on your plant)
http://en.wikipedia.org/wiki/Photosynthetic_pigment
the source for high power led I found is http://www.roithner-laser.at/
quite expensive but getting cheaper, still on a watt per € tubes still rule.
Led advantage is ease of control, getting THE right wavelentgh for growth of you plant and not algae (if only I was sure of which one it should be for my tank)...

[Reply #24 on:]

The RGB led's I've ordered have a blue wavelength of 460nm and RG of about 525 and 625nm. I'll have to work everything out to get all 3 working well. I think I'll go for 600ish nm as that seems to be a good all around bet.

Lots of stuff to figure out still....

[Reply #25 on:]

I was interested in LED's because of the low heat generation. With some of the lighting you need to buy an expensive refrigeration unit to keep your tank cool. If I could dodge that cost (and lower AC bills) I thought it was worthwhile to consider.

You might also read the papers on water movement in the link I posted earlier. I would think it would apply to freshwater too. If the plants can't get to the elements they need for photosynthesis then all the light in the world won't help them.

[Reply #26 on:]

Awesome thread. I'm considering a similar project.

Anyone interested in LED for aquariums should check out the DIY forum on Reef Central, and the LED threads on nanoreefs.com. In both of these forums, a lot of the groundwork is laid out. It's important to get the right LEDs in terms of color spectrum, but also efficiency. You're going to want the highest-output bins you can find, of a high-output LED like the Cree XR-E or Luxeon Rebel.

[Reply #27 on:]

Been on nanoreef.com for quite a long time. Some really good info there. I'm not going to go with the high output LED's because I thought it'd be cool if I could show off to my friends by having the lights change color (not all the time).

After looking at all the links everyone's posted I feel pretty confident that the LED's I have ordered will work pretty good. The red provides 460nm and green/blue provide 600/615nm. That's pretty close to the optimum values.

All I need to get started is the parts! Waiting for them to arrive sucks so much.

[Reply #28 on:]

What did you use for a pH sensor? I checked your Wiki link but didnt see it listed.

[Reply #29 on:]

Here you go:

http://reefprojects.com/wiki/PH_probe

We are still working out details for a better way of doing pH though.