Vented hoods and CFM question

[Cork144]

Reading online, says for a lot of 6" vented hoods for 600w bulbs, that you shouldnt use more than 2 in a line with a 6" fan, I am planning 3 rows of 3 hoods, a fan for each row, will I be better off using a 8" fan to push through 3 6" hoods?

it will be about 4/5 meters of hoods+duct in each row, 150mm diameter ducting, guess this means for every 2 foot of duct, will be one entire cubic foot?

 

[yocs]

it depends on what the fan is rated at, how many cfm? I would get a fan rated for more then you actually need and use a fan speed controller.

 

[Cork144]

All fans I look at are rated in m3/h, us bloody brits!

Using a converter quick, I will be using rhino twin speeds, 390/760m3/h, which converts too 229/447cfm

 

[Cork144]

P.S. I dont know what CFM I need to vent all 3 hoods correctly, hence why I'm looking for someone to enlighten me

 

[stoned-trout]

a lot depends on the hood design.. I ran rows of 3 600s on a 4oo+ cfm fan using cool tubes ....no issues...I always in general buy biggest fan and dial it down..but hey I had 3 new fans layin around already...yeehaw

 

[Cork144]

Definitely going to go with vented hood reflectors, even then, there is so many designs, but the UK isnt as blessed in choice as the US seems to be

 

[stoned-trout]

anything I want delivered quick here..or I could actually go to grow store...online is easier...yeehaw

 

[Cork144]

I will do my best with whats available here

 

[stoned-trout]

I would look for smoothest airflow models if ya can go to store and look..some designs are more restrictive than others....yeehaw..I took the trade off for good airflow,, over best reflection and coverage using cool tubes...cool tubes aren't as effiecent light wise and coverage is less than optimal....always go with biggest fan and ducting you can...you can always turn it down...buy 8 inch everything if possible..i would rather have a fan not running full speed as theres no more to adjust then..but hell fans aren't that expensive my last were 99$$$ each on sale..heard gh bought out CAP after the bankrupcy ...I always had good luck with their gear ..only a few failed ballasts but its covered by my growstore warranty....discount hydro rules

 

[jav2043]

I ran 4 8in hoods inline 600 watts each with no problems. Not sure if 3 would work but not worth the trouble to find out. Good luck