Hoppy

Hi Hoppy, I'm glad I found your posts, I hope you can shed some light on my situation (mind the pun).
I have a 55gallon fresh water tank, I currently use the regular LED lights that came with my starter kit and am keeping low light plants for now. I would like to upgrade the lighting to be able to keep more interesting/prettier plants.
I'm getting a lot of contradicting information from my research on the internet as to what type of lighting to get, flluorescent vs LED's. I need a light strong enough to reach the depth of 24" and am overwhelmed by various considerations such as watts/PARS/kelvin/lumens/colour temperature...
People who have fluorescent swear by it and say absolutely do not get LEDs and those with LEDs strongly urge the use of those.
I found your charts and thought maybe you could help since you seem to know a great deal.
Thanks so much for your time. My fish, plants and I appreciate any help

If I were you I wouldn't use any driver that isn't dimmable. There aren't a lot of them available for that much current, but there should be a Meanwell one that is the same as that only dimmable. I think I would keep the two rows of LEDs closer together, and rely on the spread of light to get the whole substrate lighted. If you use 60 degree optics you should be able to light the whole tank with the rows about 5-6 inches apart. And, for that a single heatsink about 6+ inches wide would work. For that much current the heatsink needs to be a good one, and some fan cooling will probably be needed. If you use the calculator spreadsheet in http://www.plantedtank.net/forums/di...-tank-led.html you will know all that I know about how much PAR you can expect.

hey hoppy. love your work, the led guru. i would like to upgrade my led fixture. i have done a DIY one before and thanks for your help on that one. at the moment i am i am running 12 cree XML-t6 at 700ma. what i was thinking of is buying 2 of these http://www.rapidled.com/mean-well-lp...urrent-driver/ and running 9 of the cree xml-t6's of each of these and building the heatsink myself. this is going over a 4 foot med planted 60g tank, dosing dry ferts and co2 injected.

what i wanted to ask your help on is
1. is there a better driver out there that i just cant seem to find that will save me from having to wire up 2 sets of 9 at 1750ma
2. is this going to be overkill on the lights?
3. what would be the best way to arrange them. i was thinking two 4inch wide heatsinks running the length of the tank. if the tank is 18inchs wide then one running say 6inchs from the front and the other 12 inchs from the front.

thanks man for any help you can offer
lindsay

I have never grown HC, and my experience with glosso was limited to trying out the dry start method. So, I can't comment on use of T5NOs for growing HC/glosso. I also have never used NO lighting, so I can't comment based on my experience with them for growing any plants.

In your experience, can T5NOs grow HC/glosso carpets or ludwigia?

Hm, here's a link to his site:
http://unclenedsfishfactory.com/

You probably don't know him, or you would've recognized his name instantly. :P

Uncle Ned? No, I had a lot of uncles, but no Neds.

Hey, do you know Ned of Uncle Ned's in MA? Your avatar really reminds me of the one from his website homepage.

treelimbjim, that other post was done back when I was still trying to make sense out of designing a LED light. I wouldn't recommend following that method now. The calculator is based on more data and more varied data. If you have taken some PAR measurements with other configurations I would appreciate receiving the data so I can see how it fits in with the other data I have.

This is still an evolving design process, but I haven't seen a better process.

Thank you for your contributions.

Trying to answer "How many (and type) LEDs to use my 70 gal?" or simply, "Is 24 XPG enough? 36?"

I've been estimating with spreadsheet V.3.

Tank: 48wx18dx20h, 3" substrate

Frame: 1.5" aluminum extrusions, 3 x 48" rails on 5.25" centers.

Mod/add:
Table for PAR est. for L,M,H light (see below)
LED height: Tank_height + LED_Height_above_water - Substrate_depth
Conditional format: 1) PAR background is blue, green, orange for L,M,H light. 2) current background is red when >rating.
Table for Spread with LED_Height and Cone_Angle

I'm not clear about how the "rows" work. I'm trying the geometric mean of LED_spacing and my LED_row_spacing.
Trying to validate the calculations, I ran across 84212-designing-building-led-fixture-22.html#post1102937
... and the spreadsheet isn't coming close to real world observations.

Where to go from here?