Upgrading tent from 2x2 to a 2x4, Fan and lighting question

Current tent is a 2x2 with a 190 CFM 4" exhaust w/ speed controller and a 4" inline draw 100CFM. Reason I mention this is I’d like to use these 2 fans on a new 2x4 Gorilla tent and making sure I’ll have enough fan power for the new size?? I have a HLG 135W QB, but have other plans for this light, not in the new tent.

Lighting choices: HLG LED 320W XL w/dimmer knob or 260W XL. The HLG 320W XL with dimmer knob looked like an overkill, but Kurt at Growers Lights suggested this as a top choice. Said the middle (3) panel system allows the light to hang lower eliminating the need for extra height to get center section cross lighting that the HLG 260 XL wont cover w/o extra height. Said the 320W is dimmable to 10% making it completely versatile for seedlings to harvest sized plants. Is this an overkill or a top of the line HLG choice?

If @dbrn32 sees this post, I’d love to hear your opinion of the light I may use.

While some may suggest various tent sizes, I have only the space for a 2x4 which is ideal for my grow room.

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Your fans will probably be fine. The light thing could go either way. The 260 kit is enough light. The 320 kit is better, but probably a little more than average grower will use in 2x4. He is correct that it’s more coverage, but you also have to consider how low you are actually going to run it.

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ideal QB lighting is 30-45 wpsf,
a 260w is 32 wpsf
320w = 40 wpsf

the 260w would do great, it is just the minimum amount of light,
if u wanted total control, the 320 will give u it.!

i m running about 44 wpsf of QB and love it.!!

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What method are you using to determine this method?

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Thanks to you both for looking over my upgrade needs. It is very possible that folks selling equipment often try to sell a buyer more than they actually need to get a job done. However, the flip side of buying the maximum light for this 2x4 is that the light could also be used in an even larger tent if I ever want to upsize again in the future. If that was the case, the light I have would be adequate if the size up was not greatly different. Provided the 320 is not TOO much light for the 2x4, I should be ok for now PLUS for potential growth in the future.

Kurt at Growers Lights seems to be a stand up guy. I called him for advice way back when and asked if he had a couple of minutes for a quick question. His response was he had all the time I needed and that he was glad to help me no matter how long the call may take. I appreciated his helpful attitude, now I naturally want to continue doing business with Kurt.

@dbrn32 @SlowOldGuy

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Depends on what you consider too much light. The 320 kit at full power exceeds what is typically considered light saturation levels for ambient co2 at full power. Not a huge deal, as you can dim and gain some efficiency. But with the efficiency gain, very little reason to run that light over 240-250 watts for flowering. So you’re spending extra cash you don’t need to for your current space. If you’re ok with that for potential use, I certainly am too. But if you’re cranking her out at full power expect lower yields per watt than the members running at more efficient intensity levels.

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Having just looked at the data on the 320 earlier today, I think it’s the perfect light for a 2x4 tent. Would you rather wish you had a little more light in the tent, or know that you have enough, and can reduce it as needed when the plants tell you it’s needed?

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I don’t disagree. However not everyone is at same level of thinking vs spending as you and I. The 240 kit should run minimum ppfd average of 720 umols per second. Hard to say that is undersized.

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I totally understand what you mean in all accounts. As you guide me and others looking at my thread with your answers, is there some sort of “guide” that allows me to know my ideal power output per square foot? You mentioned 240-250W in flower. How about in veg? You have been doing this quite some time and lighting is your specialty. For new growers like me, are there resources ie charts and such that can help us know what outputs are best for plants at various stages of their growth?

Someone mentioned a light meter to me today in an unrelated conversation. Does a light meter allow us to set wattage output more accurately than simply guessing with the naked eye? Is that what the meter is used for?

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Power output per square foot is a guideline. Unfortunately, it’s a guideline that doesn’t adequately apply to modern LED fixtures.

@dbrn32 above stated:

That “720 umols per second” number is the number that really matters. Unfortunately, it’s not always the easiest one to figure out.

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@Bogleg this may seem like an odd analogy, but I bought a larger tractor than I needed thinking ahead. 100 HP seemed ridiculous to my dad as he argued I could “get by” with 60 HP. All of equipment/implements could get by with a 60 hp unit UNTIL we bought a wider plow that needed a higher hp to operate. Most of the time I ran the tractor at a reduced output with smaller gear, but when I needed the power to get a big job done, I had it.

I understand growing is a different story, but my personality is the same as the tractor. A 100 hp tractor naturally costs more than a 60hp model. But when I need the extra juice, I got it covered.

The only issue is will the 320W be an overkill and cause me issues? If not, I’ll be inclined to go with that one.

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With a dimmer, it shouldn’t cause you any issues.

I know a guy who has two of those 320xl kits in a single 2x4… I’m trying to convince him he only needs one. Heh.

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LOL…I only plan to buy ONE. Promise!

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Perfect Analogy. My saying is I’d rather have it and not need it… vs. need it and not have it

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There are guides and studies all over, and they don’t all necessarily give you the same information. You try to pluck the information that seems consistent from the sources that seem reputable and do the best you can with them.

Personally I’ve been trying to remove watts from any metric I use when sizing lights. Its impossible to do, because only a limited number of manufacturers give you the actual light output or efficacy. Then every individuals needs are a little different. Where @Bogleg you and I may see some value in having a bigger light than we need with the right tools, another may be really stretching their budget to get to the bare minimum requirement.

If someone asks me “what do I need?” I’m defaulting to a ppfd average of around 800 umols per second, then looking at led/driver match up to get close to that. Some over, some under, but more about how each component makes sense with the others and cost of course. When I looked at output of 260 kit, you’d have to be in laboratory setting to pick out a difference in intensity between 720 umols and 800 umol average. So it’s good enough for me. That ppfd average of 800 by the way is general consensus on the point of diminishing returns. That means more light than that will still grow a little more weed, but your photosynthetic energy per mol of light begins to drop.

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2’x4’= 8 square feet
260 watts divided by 8 square feet = 32.5 watts per square foot (minimum)
320/8= 40 wpsf (great)

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It is, as long as you’re willing to pay about 30% more for that cushion.

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I can calculate watts per square foot lol. why is 32.5 watts per square foot the minimum and 40 watts per square foot great?

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it amazed me that they provided a phone number.!!
no one wants phone calls anymore,
G.L. included their business card/number and some sticky traps with my lights.!

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grow sites.!!

i watch ALL QB threads.!! mwah hah hahh.!! LOL
i have accounts in GrassCity and GrowWeedEasy also.

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