I suppose the only way to really know without jumping in would be to figure out sensors used in these units, and research them. When I got the photo bio it was the only apogee alternative out. it looks like there are several devices now. 
I’d imagine any of them would be better than using a phone app. Only way to find out is research and comparisons.
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@Blitzed: Don’t forget eBay, if you can afford to have patience. I bought an open-box PhotoBio meter there recently for $100.
@Low: How are you calculating Benchmark Harvest in your spreadsheet? Are your Coverage figures taken from the manufacturer’s specs or computed somehow?
I know it’s way late to mention this, but it would be good to have the lights’ dimensions (length and width, especially).
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By wattage and efficiency/coverage. Just ball park figures. Generally 1.5-2.0 gram per watt on average. However it’s not unrealistic to pull 2.5 gpw if the light fits the area appropriately and there is some canopy management.
As for dimensions of fixtures, some of these dimensions have changed since posting this. The point of the topic was to pair lights to tents. Wasn’t a focus on dimensions for multiple fixture applications. Good idea none the less. 
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So it’s implicit that a light in the “2 x 4 Tent” category, for example, measures 24" x 48" or less. Makes sense.
You’re right that the dimensions aren’t critical info unless you’re thinking of putting two or more lights in the tent. I put three in my 2’ x 4’, yielding 75 W per square-foot.
Let’s see…at 2.5 g/W, I should get 3.3 lb! 
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I hit that 2-2.5 frequently with scrog 
if I counted larf it would be higher. I too have ran multiple fixtures in a 2x4. Up to (4) 100 watt fixtures. It’s not so much about wattage as it is coverage. This is where efficiency comes into play. Less wattage needed to get the coverage the more efficient your grow is. Singular higher efficiency fixtures will get a little more for your money for the wattage if you are willing to pay for it. Personally I’m a budget grower, I’ll buy cheaper fixtures and daisy chain to get my coverage.
@MadamCalamity pulled around 25oz off of (2) 100 watt fixtures (spider farmer sf1000’s) because she was able to dial in the coverage, and the GDP was a yielder. That’s around 3.5 grams per watt. Scrog, and dry weight.
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Coverage in a reflective tent is hard to predict from manufacturer’s PPFD maps. I found that the illumination in my tent is much more uniform than the maps indicate and PPFD is higher.
Maybe, but I don’t believe anyone makes a 2’ x 4’ (1152 square-inches) monolithic quantum board. My three lights’ total surface area is 1014 square-inches and leave gaps that allow airflow. I like the longer-term versatility of having three identical units, too.
PS - Where is the Classifieds section of this forum?
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No, no one makes a light that footprint, however there are singular fixtures that can fill that space fairly well if at the correct distances.
Classifieds are under grow equipment but you have to reach certain “mile points” on the forum for it to be visible.
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I believe 480 w will be plenty for a 3×3. Hopefully I don’t burn the house down.
That light at 100% is crazy bright. It fills the whole tent. I’ma have to put all the exhaust outside the tent I believe, guess I’ll make a dimmer switch for the monster exhaust. 
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Should be plenty for one girl.
Ahh maybe 2. Wanna make sure I can make one live before I go bushing the whole tent.
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Looks great!!!
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True – I’ve seen examples. I wanted to be certain I have enough light, though, and definitely erred on the right side: Using 600 W, my hotspot at 24" is 1380 umol/m2/s and the dimmest corner is 1214. $497, w/tax.
Makes sense. Thanks for explaining.
Why? Do you expect your plants to get that tall?
BTW, on a different note that’s relevant to your posts, I wish the manufacturers would substitute Bluetooth for cables and connectors. That would reduce compatibility issues. If they could then agree on a standard software interface, we’d have universal interoperability, like the MIDI standard did for electronic instruments.
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Got a mail back from Spider Farmer.
It won’t be re stocked but a new one will be. All good. I’ll just use the AC infinity Pro.
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@Low If you have your data in a spreadsheet, have you considered putting it somewhere we can download it from?
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Morning. I don’t think I have it anymore, pretty sure I made it first on an iPad that got destroyed.
However you can find similar tools/calculators by HLG, Cocoforcannabis, and trimleaf(I think) all you really need to know is actual wattage and total ppf output.
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I pulled the exhaust out of my five foot tent. But my 6fts I left exhaust inside. I have yet to come close to my tent ceiling height in them.
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@Low: I found a website that may be of interest to you.
It’s for an industry consortium that performs independent measurements of lighting units and compares them with the manufacturer’s specs. It has search filters that can be used to specify the size, wattage, and other characteristics a potential buyer might want to restrict the search results to.
Main site: https://designlights.org/
Horticultural lights: MyDLC - DesignLights
You need to create an account with an email address to access the site.
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That’s SICK!!! Thank you buddy, never knew such a thing existed.
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Manufacturers show the DLC certification for their products that have it, along with UL, IP65, and FCC. I doubt any of us pay attention, though, because we don’t know what DLC means.
Many of our favorite manufacturers are absent entirely from the database (e.g., ACI, Spiderfarmer, Vivarspectra, and Vivosun). Others have only 1 or 2 certified units (e.g., Kind and Mars Hydro).
We should encourage them all to join the consortium and get all their lights DLC certified. Think of how much easier, more objective, and more thorough it would be when choosing lighting to have one website that produces a list of all the products that satisfy our criteria, along with their specs.
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If I already bought a grow light but want to replace the drive with LM301 driver could I or is there more to it?
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That’s more of a @dbrn32 question. I haven’t done enough hands on electrical work to make any suggestions.
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