400 watt or 250 watt hps question

I have built a grow cabinet with a flowering chamber of 3x5x2 feet (widthxhightxdepth). I plan to put in 6 plants (3 northern lights and 3 ak4 with a scrog screen doing 12/12 from clone. I have 2 air inlets and a main 8inch exhaust fan at the top also a 6 inch wall fan included inside. Temperatures in my city are about 25-30 at day and 13-18 during night. Do you think I would be able to use a 400 watt hps or should I stick to a 250 watt.

Heres the picture of the cabinet.
View attachment 2479824

Thanks everyone. And I need your help fast cos I have to pick up bulbs tomorrow. Regards.

go with the 250 for a small space or invest in a cooltube and you could use the 400

250w imo is fine just over 40w psft is good to go

But it's recommended to use around 30 watt psft

I'd go with less plants in a Scrog that size.

ed recommends 40w min for indica varietys sats are up to 60-70w psft

and a 250w is not as efficient as a 400 600 or 1000w

dont know where you get you references from though

Thanks for correcting me Agito.

all I want to know is. If I keep the day time for plants at night whn outside temperature would be around 15 deg Celsius or 59 degree farehnite, would it be ok with a 400 watt. Ill have a fan blowing at light n one at plants.

I know I should go with a 250 but a 400 is tempting.

IMO you may get away with the 400w but at 66w psft is on the high side

have you factored in plant size as well at 5 ft you need 2.5ft for the light and light spacing. then you need to get your pots in there now we are up to 3.25ft not much room for plant and the stretch from the net
A 250w will give you another .5ft extra

Looking at the bigger picture if you dont have an air cooled hood you will struggle on plant size alone as the cab is to short and slightly to small as well IMO

got a 5imch diameter 12 inch long glass tube and got two 6inch fans. Nw gonna do the cool tube diy way. Just need to find flexible duct hose here. Any ideas?

Picked up both 400 and 250 watt with a switchable ballast. It can run both. Wired it and ran it for two hours with 400 without the cool tube inside the cab and temps reached around 34 deg Celsius. Outside was about 24 deg. Din even have the exhaust running. So I guess I should be pretty much fine. What do u guys think?

long as you can keep it at 30c and below your golden

Blackhawk149 said:

Picked up both 400 and 250 watt with a switchable ballast. It can run both. Wired it and ran it for two hours with 400 without the cool tube inside the cab and temps reached around 34 deg Celsius. Outside was about 24 deg. Din even have the exhaust running. So I guess I should be pretty much fine. What do u guys think?

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get an intake setup and you should be good

M planning on keeping passive intake for the box. The bulb would be housed in a DIY cool tube. Do you think two 2500 rpm 70 cfm fans would be fine for cool tube? One for intake and one for exhaust?

delvite said:

go with the 250 for a small space or invest in a cooltube and you could use the 400

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+1 I'm using 400w in a size about that big. Cooled hood of course with 4" tubing and a vortex 170cfm speed controlled. My cabinet Temp are right around 80f, 1 foot from the light with the room air temp around 70. I run my lights at night with the room window cracked and the room gets down to about 60-65f and the cabinet temp drops to about 77-78f (the exhaust temp from the light is commonly 90f).

IMO get a 400w dimmable so if your temps go up this summer, you can dim down if needed. I picked up a galaxy 400w dimmable for just over $140. With the ballast, cooled hood, bulb, and cordset I I paid about $275 with tax. (but I got a pretty cheap bulb)

you want a high compression fan if running a filter

you dont need an intake fan if theres an open window near the intake

Agito said:

you want a high compression fan if running a filter

you dont need an intake fan if theres an open window near the intake

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not running a filter.