HPS Cool Tube / Cabinet Ventilation?

[dennysnook]

Is a seperate fan running constantly when lighting is turned on typical in a Cool Tube type application for a 3x2x6 cabinet? I have seen a few setups that have the fan/filter inline with the cool tube all in one line. I would assume that the fan would only run when temperature is high, but it just seems that it would trigger the fans at a constant rate to keep temps down. I am trying to keep costs to a minimum, so one fan would be preferred, but I need some insight into how much the exhaust would engage. Reason being: I want to use co2 so I don't want constant exhuast which would defeat the purpose. Does this mean I need two fans, one for exhaust through the cool tube and one for cab exhaust? Or can I eliminate the cool tube and just let the exhaust vent the heat out with a regular hood. I want a 250-400 hps and temps no more than 85. Can someone please stear me in the right direction.

Thanks in advance for any help.

[hwhobbs]

you replied to mine so i'll reply to yours...

I have a 135 CFM blower (not fan) sucking the heat out of my cool tube. My cabinet is the same size as yours roughly. It needs to be on all the time or at least when the light is on. I only have the one exhaust from my cool tube and I have 2 intake fans. If you leave one end of your tube open it will act as an exhaust for the room as well. I can post pictures up of mine later.

Believe me, I was using a 400w HPS with a hood and the temps were upper 90's with all my intake and exhaust and circulation fans on. Now I have 2 intake fans and 1 cooltube, the light is 32 inches closer and my temps are low 80s.

It is WELL worth the 100$ for the cool tube

[dennysnook]

I assume that you do not use Co2. If is it constanly running, I will have to run two seperate exhausts to have Co2 in the cab so the fan doesn't suck out what I inject into the cabinet. I guess I either have to decide to get two fans or do as you said and use the end of the cool tub as an exhaust and forget the Co2. Since you clarified that it runs constantly: Is there any one out there that has experience a suncourt inductor type "cheap" inline fan solely for exhaust of the cool tube. I always see these advertised as an inline / HOOD fan but don't know if they pump enough air out to keep the light cool, but if constantly running, why not? To me, it seems that a blower type fan is excessive since there would be no connection to the cabinet space. I am trying to keep electrical costs down since I will have to run constantly under light. Thanks Again.

[RobsGreen]

Its probably best to leave the co2 especially if you don't want to waste money case that would probably do it. I've been wanting to do this as well but it has to be done properly to get the results you'll expect from it. The only way is to have the cab 100% sealed with no venting at all, have a fan cooling the light and then pump cold air into the box to keep the cab temp down. It would cost quite a bit to setup and an air conditioner would likely be needed and we know those are cheap to have plugged into the wall. The best advise I got was forget about it and concentrate on getting the environment perfect through the entire grow, that will likely give you better results then messing around with co2 when you need to vent. Good venting will keep the co2 level in the box the same as it is all around you which is plenty for plants. I also have my fan run all the time when the light is on, it would be fine to only have the fan trigger when the temp rises, I did that for a while but was worried my glass would break from the heat, its not tempered glass just regular.