400hps or 600hps in my somewhat small grow area?

Ok, I need suggestions on buying a 400 or 600 watt light. Here's some dimensions. Grow tent is 2ft deepX 4ft wide X 6ft 10in tall. I have a modded stanley fan(cfm unknown), pulling air from a carbon filter that is ducted through my 250w cool tube and then through the fan. What im wanting to know is which light would be ideal without temps getting too high? With my 250w hps the temps go no higher than 83 degrees. I would really like to have a 600 but im afraid the heat will be too much for my space. Any suggestions or own personal experience would be greatly appreciated... + rep. Lastly whichever light I get will be ran with a cool tube.

are you going to run the new light along with your 250? if so you need no more than the 400. especially for the space you have. more light usually means happier plants but too much heat and the light wont matter. i use a 400 hps with over 200w actual cfl's watts are watts but my heat is more manageable this way. my advice "bigger is not always better" think more practically, and figure what works best for you. goodluck. and dont worry about the rep. your not old enough

I am going to replace my 250 with a bigger light. Yea the 400 sounds good to have. I dont wanna get the 600 and it be a jew oven in my tent...hahaa... no offense.

none taken. i think if you can manage the heat it wont be a prob, but for your space you should get much penetration and coverage with a 400. not trying to downplay the 600. just saying. and if your going to need side lighting with cfls' thats more heat to take into account. whichever way you go, im sure you will be fine.

I would go with a 400w light for your space. I think if you go with a 600w, you will really have too many problems with heat. Good luck.

The I's have it!! Go with the 400 you'll be putting down about 50 watt ft2 and you only need 30 to 40 a ft2 to flower cannabis anyways. The 600 would give you bigger buds, but in your space that might be overkill.

since u got a small space u wanna yeild as much as possible per plant, go big or go home. 600 is perfect for for ur space. what u should do is get is a lumetec ballist like I got, I got a switch on it that goes from 250,400,600 and 600 super lumen. big lights equal big buds, tight nugs. As for the heat i use a 400cfm inline fan and it cools my tube so good I can place my hand on the tube. my grow room is only 2-3 degrees warmer. If u get the 400 ur gonna just end up wanting the 600 in a few weeks. can never too much light and if u decide to make a bigger grow room in the future u'll have what u need already

This chart is pretty accurate... wattage + cfms = grow temp increase over ambient temps. It nailed my temp increase perfectly. I'm re-posting this because temps and ventilation are critical areas, thought you might be able to use it.
https://www.rollitup.org/blogs/blog12353-ventilation-chart-calculator.html



I could be wrong, but I think that temps will correlate if volume is increased/decreased while cfms and heat output remain the same. Volume goes up, exchange rate goes down, temps remain stable. That's just a guess though.

Dude get the 600w. Then figure and do what you gotta do to air cool it. Go big cause you dont wanna get the 400w then after your 1st harvest wish you had gone a little bigger.

I can agree with that!, as long as you can control the environment with the six. More light = more buds, right?

Get a 600 dimmable ballast. Cut it back as required, then in the colder months you can run the 600 wide open. Also try running your light at night to help with the heat issues. Dimmable 600 will provide you more flexibility.

i use 400 so i say 400 lol.

Hoenhiem said:

are you going to run the new light along with your 250? if so you need no more than the 400. especially for the space you have. more light usually means happier plants but too much heat and the light wont matter. i use a 400 hps with over 200w actual cfl's watts are watts but my heat is more manageable this way. my advice "bigger is not always better" think more practically, and figure what works best for you. goodluck. and dont worry about the rep. your not old enough

Click to expand...

I would go with the 600w especially if you plan on using cooltube. You will be much happier with the single 600w than the 400w and or using both the 400 + 250. he amount of lumens you will get out of the 600w is well worth it, and the heat difference between 400 & 600 is very very minimal, I presently run a 400 & 600 in my room and the 600 is in a sealed reflector and I only have it hooked up to a small 4" inline fan to pull some of the heat out and does a great job. I paid $14 for the 4" inline which is only 80cfm but it does enough to pull the heat out of that reflector and keeps my plants happy happy.

Thank you everyone that posted for their input. Im liking the idea of a switchable 600 so that if I temporarily have heat issues I can turn down the wattage to 450 and manage the temps until I can get something better, or run the 600 during winter and it will be golden. Thanks again.

glad you made a decision. a dimmable ballast is a great idea, just make sure you plan your garden. many ppl go bigger than they can handle and realize a little too late that not only does more light = bigger buds, it also = bigger plants. goodluck bro and watch that stretch it can take you by surprise if you dont plan for it.

Yea im glad you brought that up Hoenhiem about the taller plants. I plan on flowering at 6 or 8 inches to make up for the height. With my 250 i flowered at 12in and they are almost 4ft tall. It kinda sucks having a 12in tall bucket but oh well...