How much light is considered too much?


Reefing newb
While I am going to be able to dim the LEDs on my tank how much would be considered too much?

Of the guys that have built their own lights, either from RapidLEDs or from another source, how many LEDs did you use? My tank is a 150T with the following dimensions of 48" wide X 24" deep X 28" tall. I know I need good lights to be able to get down 28" of saltwater, and I am using 3 watt LEDs. I just need to know how many I should put up there. The power supply I am using for them is from an old HP printer we no longer have. It's output is listed as 31.5v @ 3.17A so I have enough power for three strips of nine LEDs and maybe a few more in a fourth strip. I don't want to try a full fourth strip as it would make it to close the the rated output of the power supply. But even still three strips would come to 27 LEDs... Do y'all think that would be enough,, or do I need to add more or take some away?

I ordered enough LEDs to do my freshwater tank, my saltwater tank, and probably enough to light a fuge and have many spares as well. Here is a list of what I have on hand here.


  • 20 X 20K White
  • 20 X 10K White
  • 9 X 455nm Blue
  • 15 X 465nm Blue
Spare (Or soon to be wired)

  • 5 X 455nm Blue (Spares)
  • 10 X 410nm Ultra-Violet (UV) -- Soon to have some wired up
  • 10 X 520 - 530nm Green -- Soon to have some wired up
  • 10 X 10K White (Spares)

What I would do is start from 10-15% and basically acclimate your lights to your tank, when or if corals start to not like your lights or bleach/change color go 5-10% less on your intensity. :twocents: