I've been looking into this myself (title of thread). I currently use 2 1000w hps and would like to switch to leds. If you look at the umole charts on the A51 site and the ones Greengenes/Tags posted in his thread on page 9(Tags high efficiency lighting garden) and compare them to what you'd be getting from a hps, leds seem like they should be killing it. But then you look at some of the grows people are doing, and although many of them are great grows, the yields just don't seem to be there like the umole charts suggest they should, so I'm starting to think there may be something missing.
I run 3 3x4 flood trays arranged in a 4x9 rectangle with 2 1k lights (in a 5x10 tent). Perpetual harvests. My worst run (single 3x4 tray) was 20 zips, my best was 26 and I don't even have it dialed in all that good(if you do the math I'm hovering around 1gpw).
2 A51 lights would fit perfectly over each flood tray, yet for the yields to be comparable I'd have to be getting a minimum of 20 zips with a lot of room for improvement. That's 10 per panel (or 1.5 GPW minimum). Looking at the specs it seems easy to achieve, but I'm just not seeing people actually hitting those #'s. (But to be honest I haven't been looking real hard, still trying to learn the "science" behind the technology).
One thing that crossed my mind is I've read that the plants don't uptake nearly as much water under led's as they do hid. It's been said as a good thing, but it makes me wonder if that reduced uptake means they're not uptaking enough nutes to get the yields we see under hid lights.
Hopefully someone will chime in and point me in the right direction because I really do want to make the switch, just not at the cost of reduced yield.
