Cool Tubes

[whazzup]

Oh but I'm not refuting the fact that the glass stays cold, not at all, though my plants had light stress when they grew around the tube.

 

We try to grow pot as efficient as possible and as a rule if you yield a gram pot average for every watt of light at an average flowering period of 9-10 week you do a good job.

[The Hash Nibbler]

Hey Whazzup =), mate, you got it lucky in Holland, you don't know what heat is. .

 

Try summers nights where the temp doesn't drop below 25 degrees celcius + and days that scorch into the low 40's. For a lot of us cool tubes are an essential to run in summer, we don't have a choice, it's either use them or raise the air temp in the grow area another 10 degrees. Air conditioning is expensive to run 24/7.

Agree with you on the dust/dirt build up in the tube lowering output about 10%, will be cleaning mine this morning as it's a bit crappy.

Your plants may of got a bit of light stress growing around the tube, but try the same with an open reflector and it would of cooked them.

 

I think they are a necessary evil in our climate, but I won't be growing in Summer again, just too bloody hot. I want to use open reflectors as I don't like the light foot print of the Tubes or the amount of reflected light delivered by them, just limited by ambient temps here.

 

My mum used to say, it's better in cold weather, it's easier to put on more clothes, than to try and stay cool in the heat when your already naked.

 

Gh72

[whazzup]

yeah you're right of course. I have an American girlfriend (imported her 6 years ago on the day that Bush stole his second term) who wondered why Dutch houses have no airconditioning... It's simple. First, that's cheaper (typically Dutch standard answer), secondly you would only need it 5 days a year .

 

And when that happens everybody complains about the hot weather!

 

But even in the Dutch greenhouses the winter is very often better for crops than the summer, purely because of the climate in the greenhouse.

[Pleb Scrubber]

Well I have just installed my new cool tube.

I was desperate to get the room temp down.

 

The other day temps reached 37 degrees in the grow room and half my newly germinated babies passed away...

Their tap root was all soft and mushy (root rot?) was the first time I tried raising them in rockwool too, (too wet?)

 

Everywhere I read about germinating says, keep them warm, keep them wet... but they died from too much warmth and wetness.

 

One problem with the cooltube is the bulb (mh) rattles under the rapid airflow around it, the wire inside the bulb shakes against the glass, I hope this dosnt reduce the bulbs life...

[whazzup]

If the bulb rattles then I almost know for sure your air speed is much too high. It should just take the heat away from the lamp, how much are you pushing through your tube, what size of lamp and what diameter tube do you use?

[Pleb Scrubber]

well Ive changed my setup a bit since then, its hard to explain...

 

now I have 2 x 150mm cooltubes connected in series, in seperate grow areas...

then via 6M of duct with a few bends in it to a Y-duct join, the other input to this join is the out-take air from the room.

 

After the Y join to a 250mm centrifugal fan, after that thru another 4M of 250 duct, then its free

 

I have a 150mm inline fan between the 2 cooltubes, and it only turns on when the first light is on (12Hs day)

250mm centri is on 24/7

 

 

I found the lamp holder is mounted to a very flimsly bit of metal connected on ony one side, I jammed a small block of wood between the inside of the tube and this lampholder mount to stop it wobbling around.

 

Also I disconnected the carbon filter from the room out-take, because of the air resistanc it added, a lot more air would suck thru the cool tubes than would exit the room, increasing airflow thru the tubes too much.

But in a few weeks ill have to reconnect the CF

[Darth Desolas]

I run various setups with cool tubes and find them almost indispensable in the WA summer. Any light losses from glass interference or dust is much more made up for by the increase in luminosity due to being closer to the plants themselves.

 

I currently have a triple setup in a 2.4 tent, with two horizontal and one vertical dropped in the middle. My present arrangement is going to change this weekend though as it was a hangover from a previous crop. The air is pulled out via a centrifugal 150mm fan, with a pre filter on the two inlets.

 

You have to even up the flow inti the two ends of the inlets so that you don't get all the flow coming through one branch but not the other. But with judicious use of ducting taps and a bit of filtration on the ends of the ducting it works wonders. Rarely do I see temps significantly above the temp of the air being pulled into the room, and the centre light dropped between two or four plants just thickens them up beautifully.

 

More typically though I run a pair of 600w cooltubes pulling air from outside the garden, through the lights and then out to the outside air.

 

Hope that helps!

[Darth Desolas]

Oh, and cos my iPad can't seem to attach pictures, here's a diagram showing the triple setup and a more typical twin tube setup I run.

[whazzup]

I'd rotate the T 90 degrees to the right and you have to keep the ducting at both sides about the same to prevent big differences in the two tube systems. Air always takes the easiest way first.

 

Secondly I would always blow, not pull in a cooltube system. First of all you warm up your fan considerably (not good) and secondly when you push instead of pull you create overpressure in your cooltube ducting. Any small leaks will not lead to any smells in your exhaust, you you can keep it a complete separate system. I prefer to blow away from the lamp holder to prevent intense heat reach the wiring. You can make a case for doing it the other way because that is more aerodynamic .

 

If you can use a prefilter before your air inlet to keep your tubes clean!