Ligthing and Ventilation Q's

[elwood]

Hey everyone I haven't posted in a while but am looking at purchasing a new set up soon and just had a few questions. The system I'm buying will consist of the following:

 

- 1.2 x 1.2 x 2.1m Mylar tent

- 1.2m Cooltube

- 250mm centrifugal fan with carbon filter

- passive intake

 

I plan on running 4-9 plants at any one time. Question 1: should i run 2 400w HPS in the cooltube both on analog jb ballasts, or should i run a digital 600w hps? I ask this question because i read somewhere that analog ballasts take 10-15% extra wattage, so between tthe 2 400w ballasts they could use an extra 100w or so making a total of about 900w. If i get a digital ballast though with 30% extra lumens then a 600w digital would provide equivalent of about 700w analog whilst only consuming the 660w. So if my theory is correct I would lose about 100w of light but would save about 230W of power, am i correct?

 

Question 2:

250mm carbon filters tend to come in 500mm and 1000mm, I think there may be a shorter one but I am not considering one that small. What does the extra length provide? increased surface area I know, but does this have a great affect on the air-contact time with the carbon? As i understand it most have an optimum range for air contact time to provide the best odour removal. Will a longer carbon filter last longer? Does the length really matter?

 

I would really appreciate any help you guys can offer, I have trolled the boards for a few years now and have bought a few books but none really answer these questions. If anyone knows of other posts/forums where this stuff is available can you post me a link?

[The Hash Nibbler]

Cannaversity mate, everything you need is right there. Too many question to answer from my dickie mobile on a sunday morning. Click on the Cannaversity logo below and look in ventillation and lighting section. Done. Peace. Gh72

[Naycha]

I have a 300mm x 1000mm and it is a massive pain in the ass, it was so hard to hang it. I kind of wish I got a smaller one but it's all good now.

 

With a passive intake I would probably go the 500mm though, unless it pulls easier through a bigger one I'm not actually sure?

 

Hahaha, sorry that probably didn't help at all

[drunkuncleharold]

If you are going 9 plants in that size tent I would suggest SOG or Verticle grow. My first grow in a 1.2 X 1.2 I did 4 plants DWC and couldn't even get a look at the plants in the back, that is the limit if you are doing normal bush/tree grow.

 

As far as your light question, you also need to do lumen output comparison of 400W and 600w globes that would be used, and if you are concerned about your energy consumption (as in your electricity bill) you need to put amperage of the ballast into the equation as well. Personally I run a 600w HPS on Digi ballast in my 1.2 tent. I run it verticle and took away my cooltube and it runs colder and more efficient with heat loss, no light loss from the cooltube, and larger area of light spectrum.

 

In regards to your Carbon filter you want to exchange the air 5 times in one minute, so your carbon filter to reflect this in CFM. The 1.2 tent is roughly about 112 square feet and I will use my Mountain Air Carbon filter as the example, it is the 150mm X 960mm which has a CFM rating of 580 and the proper fan to utilize that rating which is 20 CFM more than I need, but I am sure the plants will not complain with more air movement.