Ventilation?

[slthby]

Hello, noob here. I have read alot from this site and would like to thank all that contribute. I have decided to build myself a growcab. I will be growing ina Deep Water Culture system. I am in the design phase as of now. All that i have purchased so far is a 400whps and a easycool 8" ventillated hood. the cabinet will be 3.3ft. x 3.3ft x7.2ft = roughly 80cft. A third of the cab will be for mothers and clones. I know its a complicated design, but everything has to be contained in the cab.Ihave figured out how to lightproof vent and all my problem is with ventilation.i have an 8" hood so i thought i could go with an 6"inline fan on a speed controller and use a couple of duct reducers for the hood. Exhast will be filter-fan-hood-through the floor and into the crawlspace.with passive intake. It will have a total of 5 90 degree elbows just the way it is . i willnot be useing co2 so i need to exchange the air 2-3 times per min. so 80cft. x 3= 240cft x1.5x5 for the elbows gives me
an astronomical figure the elbows are whats throwing me a curve. so then i thought since i have an 8"vented hood just go with a sunleaves 8" fan 650 cfm along with a can 66 filter on a speed controller. I guess what i am asking is that going to be overkill? Sorry for the long post i hope i diddnt scare anyone off thanks in advance.

 

[Herb Fellow]

Re: ventilation ?

I'm not sure that will be overkill as that 400w hps will put out lots of heat. I vent to my crawl space also and one thing I've learned is to make sure you critter proof that vent. I had an opossum climb us mine and made quite a racket. Always an adventure in the country.

 

[slthby]

Re: ventilation ?

Thanks for the reply Herb. Ijust wanted to get someone else' take on it before i place an order. I have been researching this project for about 5 mos. sorry to hear about the critter i will keep that in mind , how about a backdraft damper?

 

[Herb Fellow]

Re: ventilation ?

I now have a screen and a dryer vent cover on my exhaust. I use an inline fan to pull air in. I grow in a 2 1/2' X 4' closet and couldn't keep it cool with my 400W. Now using T-5's. I'll break the hps back out when I have a larger grow room. I grow for personal use only and can provide for my needs with the T5's. I grow 12/12 from seed and have a continuous grow. Works great for me.

 

[slthby]

Re: ventilation ?

I guess a larger fan on a controller would be better than not having enough fan.

 

[slthby]

I stated wrong cfm on that fan. The 8" fan is rated at 750 cfm. Anyone else have an opinion. Iam going to pair it with a Grozone Multi mode fan controller.