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HPS, Tent upgrade, cooling and all that razzmatazz

Hi All


Im going to upgrade my setup after this crop (my 3rd so far only so i'm still pretty new to it all)


currently have a 2.4 x 1.2 x 1.8 tent and i started out with 3 x 600w viparspectra lights. last two yields were only 15oz from 3 plants, and 18oz from the 2nd yield, 3rd one is 2 weeks to go


after taking in lots of advice, it seems that those lights just dont output the kind of power needed for decent yields and for this latest crop i have borrowed 2 complete 600w HPS lights with normal parabolic reflectors, and new bulbs (omega dual spectrum, and Lumii Black ballasts). i have retained the middle LED for a side by side comparison..


so far the two plants under HPS are producing much larger and fatter colas so i'm sold on HPS and dumping the LED's.


a little about my current setup:


2.4x1.2x 1.8 tent

2 x HPS Lumii ballasts and omega dual spectrum lamps 600w, 1 viparspectra reflector 600w led

alien easyfeed system, 30l pots 60/40 coco 24 hour feed schedule

rhino 5" 360cm3 fan, carbon filter into rhino silent theromstatic fan controller

passive intake using 2 x 8" duct s bends for light baffle

feeding canna nutes

1400 oil filled rad for night with inkbird controller

plants are 2 x Kritical Bilbao, and 1 Incredible bulk


Im growing in my cellar, which helps to regulate the ambient air, its about 15C in winter and 18-19 in summer


my next upgrade will be to a 3m x 1.5m x 1.8m tent which will need extraction upgrade

im thinking of an RVK L1 6" fan and mountain air or similar filter. i think that gets me up to 60 x air extract per hour even with filter and ducting


my real question is how many lights for that size space? i intend to start growing 4 plants. my concern is with heat, and getting rid of it..


and the next question is cool tubes.. do i or don't I


some people love them, some hate them. Im having a bit of success at the moment using a dump fan to duct cool air towards the HPS lights, but I hav'nt used this setup in summer yet


thanks for takking the time to read and reply


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its a bit of a weird tent size. can you not get a 2 metre or 2.2 metre high tent?

anyway for a 1.5 by 3m tent you would be looking at 2x1000watt lights to cover the area.

don't use cool tubes, they are shit. use a couple of air cooled hoods.

I wouldn't use a 6 inch L1 fan, they sound like a tornado aircraft taking off. much better to get a 10 inch fan and filter and work it off a controller. 

that's what id do. the 10 incher will be running at lower rpm so will be quieter than the 6 incher flat out

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Tah for your reply


yeah i sort of expected you might say that about the L1 fan. ultimately the exhaust will need to step down to a 5" flue that goes up the chimney. 

I have a fan controller already so no issue there.


tent size is limited by the shape of my cellar. height is 1.8m max which as you can imagine means i cant grow my plants too high.


please can you explain why you reccommend 2 x 1000w lights instead of more, but lower powered HPS lights?



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economics, 2x1000s and hoods etc  are cheaper than 4x600s,

and a 1000watt hps covers 1.5metres square, so 2 would fit your space properly


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thaknks again


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I personally would not try 1000w lamps with that headroom, but stick with 600w. Perhaps 3 in that space would be fine. I would also make sure you have a decent intake fan and minimum extract as @badbillybob says of 10". 

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Posted (edited)

thanks to both of you. my thinking is rapidly changing on what to do.


regards extraction, if i get a 10" fan and its connected to a thermostatic controller, i worry that if the controller ramps up to 100" then the 10" fan might pull too much air out too quickly. would an 8" be more suitable? i reckon i need 600cm3 for a 60x air turnover. 


also i'm planning on passive intake as the cellar has a lovely big air vent to the outside air and i like the idea of having the whole cellar space in negative pressure for odour control. thoughts?


regarding lighting i might stick to 1 600HPS per plant then

Edited by Buddist_Monk420
forgot detail

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1 hour ago, Buddist_Monk420 said:

i worry that if the controller ramps up to 100" then the 10" fan might pull too much air out too quickly



Get a SMScom Hybrid pro 4.5a.  Expensive but effective. It has a maximum setting knob to set your maximum speed obviously:)

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