fan size

[tomo1250]

Hello, I have been reading grow forums for the last month or so and need some advice for my first grow. I have a 3’w X 2’d X 6’h metal office cabinet I plan on using for this grow. For my flowering area I plan on using 2.5’X 2’X 4.5’. I will be using a 250 watt air cooled HPS lamp with remote ballast. I will be using a carbon filter for air filtration with passive intake and separate fans for fresh air exchange and light cooling. Now my questions are: how large a fan should I be using for lamp cooling and fresh air exchange? Would a 150 cfm fan be sufficient for cooling the lamp or should I go to a 250 cfm with a
speed control. I realize that the fan through the carbon filter should not exceed the filter rating, how large a filter should I use for this size space if I plan on growing two or four plants in scrog. How close to the maximum filter rating should I be for this fan? Any help would be appreciated.

[Parabola]

is the 150 cfm the smallest you can find? you are dealing with a total grow volume of only 36 cubic feet. So a 150 cu ft per minute fan would replace the total volume of the air of your space every 0.24 minutes (14 seconds).

[tomo1250]

The 150 would not be replacing the air in the grow cabinet only in the enclosed light for cooling. The second fan attached to the carbon filter would be replacing the air in the cabinet. How often would the air have to be exchanged in the cabinet for fresh air for the plants? How large carbon filter would I need for approximately 25 sq foot area and what size fan would I need to go through the filter at the rate of air exchange? Am I looking at this wrong?

[Parabola]

i did a search to see what was available and the smallest combination filter and fan available was here

for a filter: Can-Filters 2600

http://homeharvest.com/airpurificationcharcoalfilter.htm


matched with: ActiveAir 95CFM Blower System

http://homeharvest.com/climatecontrolexhaustfans.htm

you could wire in a dimmer switch to give you control over the fan's speed.

[tomo1250]

thanks a lot for the input Parabola. You think that the oder would be handled sufficiently with that size filter with two plants? four plants? Would four plants be cramped in a 2 X 2.5 space in a scrog grow?

[Parabola]

You think that the oder would be handled sufficiently with that size filter
yes it should handle the smell.

Would four plants be cramped in a 2 X 2.5 space in a scrog grow?
it depends on how much vegetative growth they get, among other factors
are you doing cuts or from seed?

[tomo1250]

From seed. In the future I hope to be starting from cuttings.

[Parabola]

start with four to six and just keep the best two girls to flower out. only veg them till they are about 8"-10" high max. you aren't working with very much space so that is what I would reccommend. someone else may have other ideas and there is more than one way to pluck an oyster.. good luck with your grow man. take some pics and let us know how it goes.

[justcurios]

sounds good p. be selective