I have 390 1-watt LEDs on my 250 gallon reef. 2/3 are white, the rest are blue. The lights hang 12" off the surface and the water is 30" deep. These are not expensive LEDs, but over the past few years I have seen explosive growth of my soft corals even on the sand floor, as well as excellent growth of my SPS
set up higher. I do not think you need 7 watt LEDs to grow coral. My experience has been completely different. My background was in lasers and other solid state light emitting devices, so I have some knowledge of how these work. The lens used on the LED
controls the illumination field, a bigger effect than overall power. I pay $300 per 130 watt panels. So I have $900 in lighting (3 panels) for a 250 gallon, that replaces 750 watts of MH
. Reef is 20 years old.
I have 3 watt LEDs on my algae scrubber. Only difference is the fixture is a bit smaller. I can certainly grow coral deeper than 1' as previously stated with the 1 watt array.