Lighting distance vs lumen ratio

[Mak Bo]

Hi,

I'm having a test grow in 90x60x150(3x2x5) tent. Currently i'm using 250W MH for veg and 250W HPS for grow.

I'm cooling it down with cooltube with air from outside. In future i was thinking 400w. But since temps outside are going up i've noticed that at day time i have to raise tube from about 20cm(8') to 35cm(14') for temps aroud 25C(77F) above conopy. That means that lumen output falls from 19500 to 6500.

I think i could use 400w without any problems in winter.

My questions is: are there any advantages from using 400w and get lumen outup of 6500 vs using 250 with same output of 6500.

I know that with 400w i would cover biger space but that's about it ?

I hope this make any sense :no: :dance2:

 

[Mak Bo]

I've seen that some are growing in tent 80x80x160 wich is about my size with open reflector 400W hps + air pump + carbon filter.

I guess it must be pretty hot if lights are to low, therefore lights must be quite high to keep things cool above conopy.

So how is it worth to have 400w instead 250w?

 

[namvet25]

If your running a cool tube with a good blower and drawing cool air in running it through the cool tube you shouldn't have to raise the light to change your temp.Is your blower fan big enough? The light that has the most lumens would be the best.

 

[Mak Bo]

Night air is around 5C-10C so there is no problem. At day is around 20C. Cooltube is 150mm, the fan is 125mm, max flow: 380m3/h = 220cfm.

It's funny because glass is cold or little warm on touch but the heat still keeps coming down directly from the bulb = it cooles the cooltube glass but not the bulb?!?

I guess i should go with stronger fan. The problem is: the holes that goes to roof are only 120mm.

- - - Updated - - -

I could try 160mm fan. flow:800m3/h =470cfm but i don't know if that would be ok because of the holes and pipes leading to roof that are only 120mm? Also my tent holes are 130mm, so i got a little bit of a problem here ...what woudl suction pressure do since i have to use 125mm pipes, any idea?

 

[namvet25]

Where do you have your blower mounted?

 

[Mak Bo]

between tent and roof exit

 

[namvet25]

You should have the blower mounted just before the light blowing air through the light than a flex pipe from the other side of the light running to the exit hole in your tent.

 

[Mak Bo]

I get it that the fan should be installed 'directly' to light. But should the pipe from the roof with fresh air be installed to the fan or not?

 

[Mak Bo]

pics:

As you can see i'm not sure if i have enouhg room to put fan inside the tent. Any suggestions?

1. intake

2. out from cooltube and back inside - fresh air for plants.

3. inside

cooltube reflector: http://www.hydroponics.eu/lighting-...-s-44/xtra-cooltube-150mm-reflector-9580.html

4. temps when out temp: 10C, distance from conopy 16cm (6'), fan working at 15% of capacity and circulation fan blowing just above the conopy directly under the light.

 

[Mak Bo]

I have this kind of crazy idea. My tent is in room where there is no light so there is no need for maximum light proof at sleep time.

So to get the fan directly to cooltube i would cut from top to bottom downward(on the right side) and put a zipper in it. That would give me enough room for install fan and intake pipe.
Zipper would keep things closed enough to have closed environment for plants and at the same time would give me space for installation and moving fan up and down.


So guys please let me know what yout think. Could this work or. is it just silly idea?
I won't blame anyone if a take acction according to you comments