MarsHydro FCE4800 for a 4x4 grow?

Depending on price difference, i'd go with the FC series, but both are good lights. i trust samsung diodes more than bridgelux diodes. as long as their spec sheets have similar longevity, then it is unlikely you'd ever recoop price difference.. or it's be so similar it just doesn't matter much. The FC series is a goodlight to compare to, if oyu have to choose somethign else or want to look around -- good heatsink. Good ratio of watts per diode. If this deviates from OEM specs of that diode, the longevity and efficacy falls precipitously and usually coincides with lies/misinformation on spec sheet in those contexts. With samsung you want .20-.25watts per didoe for a high-efficacy light, as the FC4800 has. I;m not sure if the bridgelux have same power use.. would have to check their website, not mars, and see what their specs are based on. make sure any light you buy with those chips matches or nearly matches that power per diode no matter the brand of diode. Then you can expect to have the same longevity, power and efficacy... So, the FCe-4800 specifically in a 16 sq ft tent... will focuse on mature vege and flower plants, not seedligns and special needs contexts... apply common sense dimming for those earlier life stages. So, focusign on greatest requirements of your light during grow process... overkill for autoflowers in 16 sq ft. you likely want this dimmed a good chunk or hanged futher away than normal from canopy - more wasteful with watts further away but will result in a more even distribution of light and greater penetration of stronger light deeper into canopy. may or may not be worth it, fwiw. Would need to compare some larger smaple result to figure it out, i bet. At 100% this light produces 1331 umol/s of PAR. Let's jsut call it 1300. And, 16 sq ft is roughly 1.5m^2... readay to use this information to figure out a rough PPFD, now. 1300 / 1.5 = about 850 PPFD (just to keep numbers rounded since these are ballpark figures as far as their use). 850PPFD is great over 12 hours, but is eventually going to damage plants over 18 hours even if they avoid it initially. This assumes ambient co2 levels, that do vary. Over 18 hours this is roughly 55 DLI. Even if a plant adapts to this level of light and shows no symptoms, it is not actually resulting in more photosynthesis beyond what the atmospheric co2 and temp/rh combo will allow per day. it'd just be pissing watts out the window for a useless extenda-penis effect. This would be better for boosted 1200-1300ppm CO2 and tightly controlled temps/rh. You might make use of 55dli in this context. This is no accident. It is a very nice light that was clearly designed to fit a 4x4 for all contexts even if it needs to be dimmed for lower needs of longer hours of operation for autoflowers. 35-40 dli is about all a plant can handle per day with typical ambient co2 and a temp/rh that at least avoids problematic ranges. observations with trial and error before it adapts to too intense light will allow you to find a good DLI target for your other environmental variables (temp/rh/co2). future reference for photoperiods, because it'll be good for those too in a 4x4: 850 PPFD is 36.7 DLI over 12 hours. I'd probably use a 13/11 schedule for photoperiods in a 4x4 = 39.8 DLI (1/12th more DLI to start before observe/adjust). so, that's a great intial target DLI to start, then observe and adjust - long before a plant can adapt to extreme conditions of light. the resulting internode length is your guide to adjusting light intensity from there. forget aobut target dli at that point.. that concept was used to start, and now it is about observing reality of results. Back to autoflower context: In this particular context, i'd dim the light to ~70% with a hanging distance of 18" and run on a 18/6 light cycle. This puts you closer to 39 DLI to start. ( a tad higher due to rounding above). from there you may need 5-10% power adjustment either way at most without any need to change hangin distance. if plants grow a bit closer than 18" late in flower, that's fine. just watch out for bleaching and HST if you must. Early vege use i'd hang it much closer and dim it more. This will save watts and have just as good of results as anything distance/power combo can give with same resulting DLI. this takes more guessing as to how much closer/power etc.. but if you have a lux meter app, you can just make sure you get similar lux readings in central area of canopy as you had when hung at 18" / 70% power. A hanging distance further from canopy promotes better penetiration, which is only important for taller plants. e.g. because i use a scrog i can reduce my watts used while providing awesome DLI to a perpetually 4-6" deep canopy as i train it horizontally. There is no need for good light intensity deep into a canopy if it doesn't exist. I have awesome light hitting every single leaf at this stage of growth because i use a scrog. as it goes vertical, i shift strategies and amp up power and increase to a normal 18" hanging distance. The same relative intensity hits the top of canopy, but what improves is the intensity that hits 12-18-24" deep below canopy. This is due to how light spreads from a single point of a light source according to the inverse square law. Numerous well-dsitributed diodes reduces this effect, with overlapping footprints. but it is still fairly profound. == get better lower buds... but remember you cannot polish a turd. I.E. it's not a miraculous in effect. 18" is usally the proper hanging distance to avoid light damge for most bare-style lights (usually want a bit more with a QB framed light). When you look at par maps, this distance usually gives you a good overall average PPFD (an 'entire area' measurement) but also minimizes deviation of umol/s readings (PPF) from center to corners+edges. You compromise up to a point as long as you don't lose too much PPFD (resulting DLI is still most important) in this context, you could go 100% but probably need 30" distance? it's tough to guess.. but could measure at a normal 18" and 70% power then amp up to 100 and raise the light until you see similar values at canopy in central areas. This would be the exact same startign point from which to observe and adjust. You'll notice the edges and corners will not be as reduced compared to central area as before. Not only that but light will be more intense 12-16-watever inches deep into canopy, too. This doesn't circumvent physical shielding but what light does penetrate will be stronger by comparison to a closer hanging distance.. mathematical certainty, but is it worth it? ... worth lookign into but can't assume without a break-even analysis and comparing resulting yields of various strains and large enough sample sizes etc. i'd stick to a normal 18" distance and use the light as it was designed to be used. if money grows on trees for you, amp it up and raise it until it is proper intensity at canopy.