If I knew how to find the feckin +rep button on here I'd hit u up mate. Can't find it since they changed the fuckin graphics on here. Point me in the right direction. This is a good review seein as I'm about to purchase a grow tent, carbon filter and intake n exhaust fans and, similarly, vent straight from the top of the tent 3" into my attic. I'd like to know how it all looks mate and what temp probs u may have experienced. e.g. what sort of timescales did u leaves fans on for to achieve optimum temps. At what cfm were they running? Did u find it gettin too hot or too cold in the tent at all and how did u solve that? Keep it up pls buddy, and as I said, tell me where the bleedin +rep is nowadays! lol
hehe...I changed my shit back to the old style. Went to my setting and options to change it.
I'll try to answer some of your questions.
What temp problems did I have?
First let me explain what different temps outide the tent can do to your grow.
The most important things to know about inline fans is how loud they are (if you need stealth) and how much air they can pull thru the line with all the static pressure. If stealth is not an issue than by all means use any fan to do the job. Just try to calculate how strong of a fan you need to pull your old air out or to cool your light.
It's different for every situation. You need to take into account what air is going to be feeding your room. Is it from outside? Hot or cold? Is it from inside? Warm or cool? Here is the trick. You can cool a 1000 watt hps with a little 200 cfm fan IF you are using outside air that is around or below 60 degress F. If your room was 75 degrees inside and you were using the 60 degree outside air to cool your lights and tent, it would probably stay at room temp with another small fan pulling air out of the tent.
But if the temp of the air outside is above the inside air then you will have problems. You will then be forced to use the air in your room to cool your tent. This is when you decide if you want a portable A/C or not. Or if you have central air you can chose to keep your house on 75....of course the consequences of this will be a much higher electric bill.
I have had all these problems. When it's nice and cool outside I use outside air (under 75) to cool my tent and lights. Otherwise the A/C goes on. When it is 60 degrees or under outside my tent stays around 75. Perfect shit.
But, when the temps go up, you need to counter this with higher cfm from your fans (or a port A/C). At least the one for the lights. 75 degree air can still cool your lights quite nicely IF you have enough air speed and volume going by the bulbs. The fan for the filter can still be kept on low speed if you take care of the lights properly.
Timescale for leaving fans on?
Well I have 2 16" circulation fans that stay on LOW 24/7. You can hardly hear them. I have a TD-150 (wired on low) pulling air thru a Can 33 filter on 24/7. I have another TD-150 (wired on HI) pulling air thru two 1000 watt lights. This fan is on only when the lights are on.
Yes, I waste a lot of space with the 16" circulation fans. One foot on each side of the tent, but it's worth it.
What cfm were they running?
Well this is hard to tell. You can go by the manufacturers specs but you really need a good gauge to calculate exactly what the fan is pulling. It all depends on the length of duct and static pressure. The specs might say "this fan can pull 300 cfm", but you really need a gauge at the beggining of the run to tell how much cfm is really being used.
But I think you want to know what cfm these fans run at, Here is a link to the fans and their specs:
http://www.hvacquick.com/spfnconfig.php?fm=td
I use two TD-150's. One for the lights (wired on HI), and one for my filter (wired on LOW). The fan on low speed runs at 220 cfm @ 0 static pressure. I'm running it thru my filter because the specs say this fan can do 24 cfm at .75 sp. Well that's just bullshit cause I'm pulling over 100 cfm thru the filter. AND....this is with a 10' run with 2 elbows. Working like a charm with no struggle at all.
The fan wired HI speed runs at almost 300 cfm @ 0 sp. I wired this on HI because I knew I would need the extra cfm to cool the lights. Plus the run is over 20' long with 2 elbows. Works fine with no stuggle at all. I figure I'm pulling at least 250 cfm even at this length. These fans are MUCH stronger than they say they are. It's why I exchanged the TD-200 I ordered for another 150. The 200 is as stong as a Vortex.
This is how I leave them. I won't use a speed controller cause they hum like a bitch when I do. They are quiet enough but also strong enough to get the job done.
So to answer this particular question about cfm is kind of hard. I leave them running at what speed they say they are. But it all depends on duct run length, turns, filters or whatever else may cause staic pressure in the line. Then you can use a gauge to determine what cfm is really being used.
The best thing to do is try to calculate how much static pressure will be in your line and use the fans spec sheet to see what would be best. Remember this tho, some of these fans are a bit stronger than stated.
I hope this helped a bit.
