Flower tent setup, how bad am I screwing up C02 distribution

Apologies in advance for the lengthy post. A direct link to a simple diagram of my situation can be found here: http://i28.photobucket.com/albums/c2...ps3031ad71.jpg (I hope this link is allowed)

So I bought a tent to setup in my spare room, inside the 8x4 tent I have started flowering 6 plants under a 1000 watt hps, The hood is ducted from outside the tent to blow outside air (room temp) over the bulb and exhaust outside the tent (back into the room). My first day setting up the tent I realize a terrible flaw, the radiant heat from the hood pushes the inside temperature up to 90+ degrees easily, the quick fix was to open the top half of the tent doors to allow the hot air to escape, but if the tent is going to be open half the time, why do I even own a tent?!

The remedy I found, was to remove the input duct so the inside (warm air) is pulled through the hood and exhausted outside of the tent, this easily brings the temperature back down to roughly 2-5 degrees above regular room temp (about 78) and now the tent works great for keeping light away from my flowering buds.

Now the new problem I have is this: In the closed tent I was administering CO2 from a tank and regulator inside the cieling of the tent as I hear CO2 is roughly 3x heavier than regular air and will sink, fans inside the tent stir the air around a bit but when tent doors are open I have to assume I lose C02, when I pull air from inside the tent, pumping it out I have to assume I still lose C02. My new question is this: if I administer CO2 near the bottom of my tents and the fans stir it around will I get some benefit out of it before its sucked out of the light hood? Am I just spinning my wheels here pumping out CO2 that I paid for?

Appreciate those who read through and any input given

Keep the tent sealed - You'll notice with your Co2 running, the more time you spend in your tent, the more light headed you get. You don't want that escaping into your house, so keep your tent sealed.

I use CFL's but my air flow is forced, and goes over my lamps to cool them off, and that in turn cools off the rest of my box, I'm at a steady 77 at night, and up to about 85 if the sun is also beating on my boxes (without the sun on my boxes its about 80 during the day)

My air is brought in from outside (its about 35 here) its forced in with a 6" fan, and I have a 6" oscillating fan blowing it around the lights. I use a home made CO2 source, which is near the base of my plants, and the Co2 goes down into the potted soil.

I think your issue is that you should be bringing in cooler air for your light, that will keep your radiant temps down. My exhaust does my entire cabinet, and Co2 is typically off during the periods of which I'm exhausting. Your setup is fine, and I like the idea of the halo over the light, but running 1/4" tubing directly to the planters would be fine too. I use 2 liter bottles, and they just sit at the base of the plants, the opening of the bottle just over the rim of the container, so the gas leaks out and into the soil.

I'm working on ordering some slow release yeast that will consume my sugars a little slower, this way I can setup proper tubing to my plants. Right now the Co2 needs to be swapped out every 4 days, but since I'm producing so little CO2 I have no need for a regulator or anything else with this setup. During final weeks of flowering some strains I will run up to 10 of these, but typically I just run 1 per cabinet.

Anyway, to address your one concern, yes, if you leave the top of the tent open, Co2 will leak out, but you'll also be exhausting it with your current setup. Not much you can do about that. Keep it up though :D