would the early adopters of this light say that the sat plus would work for a low light set up (no CO2) in a 40g (30x18x18)?
I have the 48" model on my 55 gallon. It's about 17-18" to the substrate (pool filter sand over FloraMax). I dose once a week with Flourish and every other day with Excel. I also put in several root tabs. I have Java Ferns, Crypt wendtii's, Amazon ruffle swords, Jungle Val and Dwarf Sag. Plants have been in about a month. The Jungle Val is going through a bit of an adjustment period, but new blades are growing. Jury's still out on the swords, as I haven't seen much growth but everything else is doing awesome - even the sag, which surprised me.
YMMV of course, but in my case the LED + is working fine for me, with a little help from Seachem