I have this on a 180 gal tank (72" across), and the actual light spans almost the entire width, providing good lighting even at the ends. I do not have any tops on this tank, so the light is suspended over the water, relying on the adjustable brackets to keep it dry. The light does sag towards the center, but I'm comfortable that it won't collapse into the water. Honestly, I wouldn't trust the brackets on anything wider than 72", once you extend them out, there is significant wiggle room, allowing the weight of the light to bend it down more and more. The 78" advertised is how far they will extend, but they will NOT support the light at that distance.The brightness is good for this tank, not great, but for the cost I'd call it a good value. Make sure you measure the total distance you need before ordering, and don't rely on the supplied brackets if that distance is much more than 72", but overall I do recommend this light for those on a budget but still needing a good solution.There is no timer. There were 2 screws missing, itty-bitty metric screws. There was some assembly required, would have been simple if the flat bar would have lined with its slot and the 2 screws weren't missing. After a little adjustment and a trip to the hardware store and it is working. Its bright. If it lasts a couple years with no issues I will like it.I recently set up my 29-year-old aquarium after a 16-year hiatus. While the old fluorescent light technically still worked, one of the ballasts was going bad and required replacement. Rather than try to keep the old lighting going, I decided to check out some of the newer LED offerings.The pet store had a $300 model that connected to your phone, had built-in scheduling, and could mimic a lightning storm.I didn't need any of that.What I needed was a simple, affordable LED light that would retrofit onto my old tank and could be turned on and off with a switch. That's it.This light fit the bill, and then some. The light fit near perfectly on my standard size 55-gallon tank. The real surprise came when I turned it on. It was stunning; the light was crisp, clear, and bright. It put the old fluorescent lighting to shame.I honestly didn't even care about the blue/night light mode, writing it off as a novelty. But as I've used this light, I found the blue light pleasing. It's also great for watching nocturnal bottom feeders work while the other fish sleep. It's like getting a bonus light. A toggle switch on the cord allows for easy switching between blue and white mode.So if you're looking for an inexpensive aquarium replacement light that doesn't have a lot of unnecessary bells and whistles, then I don't think you can go wrong with this one. Recommended.Love my light. The dual modes are fantastic. The added glow element to the tank is pretty neatThis light was the only 72" LED aquarium fuxture I could find. It's price of $159 was very good, but its not the brightest compared to other lights I have. (My Coralife LED is awesome.)The packaging for this fixture is laughable. The first light they sent was missing the brackets, and cracked on the end (still worked.) but was clearly a returned item sent to me. The replacent light had equally poor packaging (see pictures), and also has one small damaged spot in the end (see last picture), but I will keep it anyway.Overall, good for the price point, but there are better lights out there for more money.It’s been some time since I’ve shopped for a fish tank light— pre widely available LED era for sure, so when my 48” fluorescent hood light finally chewed up its last spare ballast I started researching new lights.This seemed a reasonable choice and hit the sweet spot when comparing size, brightness and cost.I have a 75 gallon, which is 48” long. This light covers the entire length. If your tank were longer, there are metal brackets included to support the light across a longer span.. if you didn’t have a glass top to rest it on. As it is, I have the light resting directly on my glass top.The light has adequate length of patch cord going to the transformer/power supply that includes an inline switch which controls the three light modes (off/bright/night time). There is additional power cord length from the transformer to the wall plug as well.The day/bright mode is definitely bright and fully illuminates my 75. The night mode is a much dimmer blue and low enough to not be bothersome unless you need the room pitch black.I use an automatic timer for my light and it’s not in a sleeping area and so rarely would I manually switch it from day to night mode, but it’s a nice feature to have perhaps mood lighting or something.I haven’t yet tested it for sustaining plant life but plan to do so and will report back.Thus far the light has functioned without any issues and is a major step forward compared to fluorescent hood light technology.I would buy again.Great light, works great on a 120 gallon tank, does need some support in the middle because it is two pieces and not a solid one piece unit, but that was an easy fix....for the price it is fantastic, those leaving 1 star and complaining are the same folks that leave a bad review on yelp for every restaurant they go to inspite of the service.Wished the instructions were easier to follow. Typical loss in translation situation. Dimmer function was easy enough. Setting up timers was a little difficult.Just received the product. Was expecting whitish blue light set but after switching on it looks more yellowish like 6k then the stated 8k. Other then that light set is working.Parfait.Arrived very fast. Nice lamp for aquarium, makes absolutely different view. Item looks made professionally. Satisfied 1000%.