I think you're right, my first run with a CMH was using a 600w until halfway through flower and switching out for the CMH toward the end, got far superior yields than with either alone. Some people do switch from HPS to metal halide towards the end of flowering anyway, I can only imagine the CMH is slightly better than that.
Ive heard tall tales and outrageous claims from these 315 watt cmh fixtures as well. Everyone joining on the hype train. And you sir are correct. Many of my grower buddys arw finding these to have optimal coverage at 2.5 x 2.5 square. 3x3 is max and thats pushing it. One buddy grows big plants and has relegated one Sun Systems 315 in a 3x3 covering ONE plant. And it kicks ass but to compare these to mogul socket sixers or thouies in yield is pinnochios nose. At least what ive seen first hand in about 4 grower friends ops. Hell...all the industry even says these are optimal for SUPPLEMENTAL lighting for flower. But there is no question these are the better spectrum for more tasty..smelly amd potent end product. Its obvious because of the cmh sun like spectrum. In veg ive heard but havent seen these blow past t5's and standard mh hid lamps. What iam getting a hard on over is the very new double ended cmh fixtures just now coming out. I like the 630 i think. And these seem like they would pair up nice with 600 watt double ended hps in a flower room. One for every one for the bees knees in quality and quantity. Again this is just what iam thinking. But what i do know is the initial claims of comparable yields of single ended thouies or sixers has not happening. At least im the few growrooms around town i have visited. The irony here is just the opposite of when LED first hit the scene a few years back. It was the manufacturers and marketing that made the bold claims that growers found out (at a pricey cost) werent jiving. With the 315 cmh...its the growers themselves making up some tall tales. Anyone notice that no real pros and veterans are making these claims and the big players with huge operations? With all this said..i want 8 cmh 630 watt fixtures. One for every Gavita 600 double iam running now. Inna checkerboard pattern. One blue..one red..so on. Iam thinking hps for the weight. CMH de for the quality. One thing is certain....the old paradigm of mogul socket HID (hps for flower...mh for veg) is gone forever. I been growing steadily since 1991 and i have seen alot over the years but nothing like the advancements and choices in the last 5 or 7 years we have made in lighting choices. Just so many it makes my head spin. Led..cobs..compact curly floros..double ended hps and cmh..plasma..Just all kinds of lighting choices i got blasted with in less than 10 years. Before that it was single ended mogul socket hid for veg and flower..and t12 floros for cloning...and that was IT!!!! Not to mention vent fans. All we had in the early days were the dreaded "squirrel cage" blowers and for smell.. "Ion fountains" and ozone machines. God what a joke those were. In line blowers and charcoal filters really were game changers. A grow tent? That was a plywood cabinet lined with mylar and you made it yourself. Lol. Enough rambling. Iam done here. Iam higher than a Georgia Pine on some Glue right now. Good thread though. Carry on growers.
When i got my first 315lec's,I was told they was just very good lights...not a replacement for anything..with a 600 over a 4x4 & 2 315lec over a 3x6 (same clone).. the 315lec out preformed the 600...in all categories.
Well I'm not surprised 2 would beat 1 600 eapecially in the proper footprint you used.
That's what I'm trying to figure out, I can run 2 315lec"s in my setup but from my understanding it won't give me the same size nugs of a 600. I ran a 1000watt hps in a 4x4 and it was sick and so was the light bill
They get as hot as an open HID bulb gets. You will likely need ventilation. Never heard no exhaust needed. Well unless it's a sealed air conditioned room.
I didn't know about the ac when I commented above.
That's the setup I ran it in...a 2x2 tray filled with 9 -1gal pots of Rich soil/feed was Neptune's harvest,with a 3x3 canopy over top.
I just think the nugs development under the lec give off that deception,of being smaller.