Fan question

[2Lazy2GetHigh]

ok i'm going to be buying some equipment. i'm thinkin of purchasing a 4" vortex inline fan for my box that i am going to build which will be 3x3x5 with 1 400w MH. when my light goes off i'd like the fan to turn down to a lower speed (or off..that's a possibility) and vice versa when the light turns on. how should i go about doing this? can i put the fan on a timer?

 

[Sauce]

You could put it on a timer but there is no way that I know of to turn its speed down on a timer. All the speed controllers have a dial that must be manually turned.

Also I would get the biggest fan you can afford. A large fan on a speed controller will be much quieter than a smaller fan on full speed. I recommend a 6 or 8" if you can afford it. I have a 6" myself, the cfm increase is worth the $ imo.

 

[2Lazy2GetHigh]

ok then i think i'll get a 6", use a speed controller to turn down the speed, then put it on a timer. i think i can do fine with the fans off when they sleep don't you?

thanks for the mad quick response btw

 

[Sauce]

ok then i think i'll get a 6", use a speed controller to turn down the speed, then put it on a timer. i think i can do fine with the fans off when they sleep don't you?

thanks for the mad quick response btw

Yeah fans off during night is ok but most people (including me) leave the fan on 24/7 to keep good air circulation going. I would think about using a small fan to keep air circulated during the night.

If you want to keep it quiet there are very quiet (< 1 sone) bathroom fans that can be had on Ebay or bought through a retailer for like $50-75 that would suffice for good circulation (~80-100cfms). The Stanley fan ($40) or modified mini Lasko turbine fan (~$15 in summer only) are 2 other affordable options.

 

[2Lazy2GetHigh]

I would think about using a small fan to keep air circulated during the night.

i'm gonna have 12" oscillating fans mounted on a couple of the walls 24/7 i forgot to add which will circulate teh air inside the box but it won't vent the box really, do u think that would be enough or would you recommend buying an additional small bathroom fan as you mentioned with 80-100 cfm and put that on a timer?

 

[2Lazy2GetHigh]

also i was thinking about using another fan to cool my light. i was thinkin about the SunGro because of the square footprint it will give off but i might go with the super sun 2 because it has 6" flanges. this would mean that i should build my box to be more rectangular since the light footprint is rectangular. regardless of what reflector i buy, i'll wind up buying 2 inline fans and one small bathroom fan for bedtime. do you think that's overkill? maybe i can do w/o the air-cooled light? unlikely since it's a small box...but it's only 400w . i could test it on my own but i wanted to get all my equipment before i move. i guess i could buy the other fan for cooling the light later don't u think.

i'm really on the fence as to whether i should build a 3x3 box or a 3.5x2.5. the footprint of most reflectors would be much better for the rectangular box.

 

[marx2k]

Im not sure if this would be a workable idea, but...

If you have 2 of the same fans back to back... one at full power, one at half power, both on times. Couldn't you have the full powered fan kick on on a timer for the 12 hours on period, then in the beginning of the 12 hours OFF period, have the other fan kick on at half speed and the full power fan kick off?

Would air pass freely through the fan that is off to get to the fan that is on?

Of course, these would have to be vortex-style inline fans... not blowers.

 

[Guest]

Turning off ventilation at lights off is not a good idea even if you have oscillating fans going due to humidity buildup. This will be a real problem later in flower and I'd be surprised if you don't get mold. You'd need to also run a dehumidifier if you wanna turn that vent fan off.

You're right on most reflectors and a rectangular box. The angled sides do provide greater light dispersion than the straight up/down ends.

I got a SPDT thermostat I wired up with a fan speed controller and a 4" Vortex. It runs slow when room is under temp and full speed at the desired setpoint. I got a bug to work out in the wiring but am pretty sure it'll work just fine. It's for my mother room though but don't see a reason why it wouldn't work in a grow room as the fan will automatically kick down to slow speed once lights go off and the room cools.

 

[2Lazy2GetHigh]

thanks redux. the box i'm about to build is gonna be my veg box so i won't have to worry about moldy buds. but i want a good supply of co2 when they are sleeping so the bathroom fan at night is gonna be a reality. i decided that having 3 fans (1 for the air-cooled hood, 1 main ventilation, and 1 small bathroom fan for bedtimes) is overkill. i think i'm just gonna go with a 6" vortex on a controller and a small bathroom fan for bedtime. OR a 6" vortex for the air-cooled hood and cheaper bathroom fan for main ventilation. those vortex fans are too expensive to buy more than one especially when my op is just startin back up. i'll keep the ambient temps cooler in the room where the box will be if i need to and i can always get the other fan later if i have to.

I got a SPDT thermostat I wired up with a fan speed controller and a 4" Vortex. It runs slow when room is under temp and full speed at the desired setpoint. I got a bug to work out in the wiring but am pretty sure it'll work just fine. It's for my mother room though but don't see a reason why it wouldn't work in a grow room as the fan will automatically kick down to slow speed once lights go off and the room cools.

that's exactly the setup i might need.

If you have 2 of the same fans back to back... one at full power, one at half power, both on times. Couldn't you have the full powered fan kick on on a timer for the 12 hours on period, then in the beginning of the 12 hours OFF period, have the other fan kick on at half speed and the full power fan kick off?

yeah i thought of that but that's expensive

 

[Guest]

Plant's don't need CO2 at night. Ventilation is only for humidity control during the off cycle.

 

[2Lazy2GetHigh]

humidity yes. untill i get the thermostat controller wired i'll use 2 fans like i said earlier.