Just How High

sonny101

Member
On sunday i will be two weeks into my first ever grow. All seeds germinated really well and look wicked. At the mo got 2 x 400w cooltubes about 16inches above plants, plants vary from 4 to 6 inches tall. I only have 4 ft of overhead height so just wondering what i should be looking at doing with the lights.
Should i keep them at this height for as long as or look to up it gradually over a period of a couple of weeks.
Really dont no what to do with this one guys, any suggestions???
 

jondamon

Well-Known Member
You should be able to get those cooltubes down to around 8inches with the correct inline fan running them.

If you cannot get them any lower than 16inhces then there is something wrong with your setup.

If you can get it down to around 10inches from the tops then keep it at this distance but 8 inches would be better.

Now you should always plan for the worst when it comes to flowering. So expect your plants to triple in size so you need to allow this when deciding when to switch to flowering.

You need to fix your lights up to the highest point they will go in your grow room and make sure you allow for the distance your plants need to be away from your light. Then measure down to the top of your pots. This is your maximum growing height.

When you have your measurement you need to divide it by 3 and this will give you the best height to switch to flowering.

So if you lift your lights all the way up and allow 10inches for the distance the plants need to be away from the light and measure down to the tops of your pots. IF your measurement for instance is 36inches then divide this by 3 would give you 12inches. If you allow your plants to get to 12inches tall and then flower you should be good to not run out of room.

Hope this was helpfull.

maybe a little long whinded. But i couldnt explain it any better lol

J
 

sonny101

Member
Cool equation J, top man.
Was just scared that 8inches they may tend to burn maybe??
Im running 2 400 cools, but the fan off it is a 6inch also attached is a carbon at the end, intake is a 4 inch blowing straight to the floor.
It wont fuck anything up if i lower the lights now then will it not??
Ill go and get a picture of the little beauts now
 

jondamon

Well-Known Member
You should be checking your temps at canopy level.

They should be under 28C/82.4F

If you cannot get them down any further then you cant,
just make sure of your temps.

J
 

sonny101

Member
got my thermo in the bottom corner of the room, running at 78 to 85 at the mo, working in a lost space you see so does get a bit warm up there. gunna go now and lower the lights down a touch and do my little calculation
Cheers Bud!!
 

jondamon

Well-Known Member
Just make sure you are exhausting the air from your lights away from the room that you are pulling cool air from. Otherwise you are just circulating warm air around.

What is the ambient room temp of your intake?

J
 

sonny101

Member
God knows, cool though, drawing from outside air from eaves of garage and exhausting through eaves on other side of garage. Will post a couple of snaps in a sec. Strange the difference from my biggest to the smallest, see what you think. Got the canopys down to 10inch now, need to lower the carbon filter chains and cant be arsed tonight, 10inch will do wont it?? only trouble is now i dont have even light spread, the little birds on the edges arnt gettin as much, will just swap around every day. Got 34 inch overally head height from bottom of lamp to top side of pot!! not much is it
 

jondamon

Well-Known Member
If you have 34 inches then you need to switch around 11inches to 12/12.

As long as you have your intake coming in from one side and the exhaust going out on the other then your temps should be pretty stable. Have you got an oscilating fan in your grow too?

You could also try using insulated ducting from cooltube to cooltube and out as this will stop any extra heat coming back into your room.

10inches should be good. If you are concerned about light spread do you use the reflector wings on your cooltubes?

I plan on making some new ones out of some aluminium when i plan my next grow. I am currently in the middle of a grow and dont like messing around too much during a grow.

Here is a link if you want to check it out.

>>>> https://www.rollitup.org/newbie-central/325988-4-plants-seed-experiment.html <<<<

J
 

sonny101

Member
Looks fucking class man top job, good thread and very well organised.
Im same dont want to be messin with room now ive started, may change a couple of things next time. Am just gunna roll wi it now, just a few pointers down the way will help. Gunna add you to my fried list if thats ok fella keep you posted, you seem to no ya shit!!! haha
what you think of my little gems then??
 

jondamon

Well-Known Member
they look good man.

Yeah add me to your friends list.

What m/3 is the fan you are using for the cooltubes?

J
 

sonny101

Member
There now 2 weeks on sunday, all pritty much the same i guess.
Dont mean to sound stupid but how would i find out what m3 it is?? all i no the guy in the shop set me up with everything i needed, all i no is i got a 4inch fan intake blowing the cool stuff and a 5 inch exhaust taking the warmer stuff.
Next time im gunna run separate fans for tubes and carbon me thinks??
 

jondamon

Well-Known Member
I take it your cooltube setup is a closed system?

as in you have it ducted from the eaves on one side of your attic through the cooltubes and out the other side of the eaves? Thus making a closed cooltube setup

You also mentioned that you are blowing air as an intake into your room, are you exhausting the air in the grow room too?

You may have better temp control if you take the fan blowing and use it as another exhaust and just use a passive intake for fresh air.

I have tried to draw you a picture to show you what i mean.

I learned this technique from a friend of mine called BONZI LIGHTHOUSE. I believe he has posted in your thread already.

J
 

Attachments

sonny101

Member
Yes sin the Bonzi dude but didnt no what QTF ment???
Thanks for the diagram top man, thats what i was meaning before, next time i am gunna do that. At the mo i got a 4 inch blowing air in and a 5 drawing the warm air out, in the room rather than the end going straight through the room to draw in cool air from outside the room its linked to my carbon.
So it goes
Carbon-----------Light-------------Light----------------Fan------------------Outside
Sorry not got a scanner!!
I would of thought but forgive me for being a neubie, but would of thought that blowing in air would reduce my temp more than using the passive method??
Next time im gunna go with everything youve drawn but still use a fan to blow in air rather than a passive.
What do you think??
 

jondamon

Well-Known Member
If your fan is big enough passive intake is the way to go. That way you create negative pressure and no smell leaves the room.

If you have your cooltube system setup like the drawing you will only need to exhaust the room with the carbon filter attached as your temps will stay lower so you will only need a passive intake and there wont be any smell passing through the cooltube system as the system will be closed from one side to the other.

Is your fan blowing in air from the opposite side to the carbon filter is taking the air out?

J
 

jondamon

Well-Known Member
DO you have your ducting in bends or kinks?

this will also reduce the effectiveness of your fan and cooltubes.

J
 
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