The Planted Tank Forum - View Single Post - DIY LED for 90cm/36 inch 48 gallon tank -FINISHED! Pics/PAR levels on page 2
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post #7 of (permalink) Old 02-04-2011, 05:57 PM
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Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,015
Originally Posted by IWANNAGOFAST View Post
My tank is a rimless 48 gal mr. aqua tank so no brace.

How would I lower the mAmps using an ammeter?
I have one of these

I was reading your thread hoppy and the closer the LEDs are the higher the par right?
Those LEDs produce a 90 degree cone of light, so the light from many LEDs hits every spot on the substrate if they are close enough, and the closer together they are the more LEDs contribute light to every spot. Mine are about 3.25 inches apart.

Originally Posted by IWANNAGOFAST View Post
Ok, I just called in to change my order to 3 of the 700 mAmp drivers, and added 6 more LEDS to bring the total to 36.

I guess I'll just do 3 rows of 12 evenly spaced instead of clumps of LEDs.

Good idea Hoppy. I'm tapping into SFBAAPS to see if anyone knows of a local source for heatsinks or aluminum channels . I'd rather not get it shipped since shipping would probably be pretty high.
The 700 mAmp drivers will work easier, because they limit the current to 700 mAmp, and, I just noticed that that model driver is not adjustable. It produces 700 mAmps and only 700 mAmps. It self adjusts the DC voltage as needed to power the LEDs. My driver has a removable cover that gives access to a couple of adjustment screws for current and voltage.

Your tank is about 3 inches more front to back than mine, so you might want to make the 3 rows a bit further apart, perhaps 4 inches. That will reduce the PAR, but probably still give you close to the amount you want. Since you don't need the ends of the tank quite as bright as the middle, you could space the 12 in a row at 2.75 inches apart, so they stop about 3 inches from the ends of the tank. That raises the PAR, bringing you back to about the amount you want.

If you don't mind a trip to Sacramento, you can find lots of aluminum extruded shapes, including about 5 sizes of channels at: And, several years ago there was a similar store in Oakland, but it may not still be there.

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