Cool tube booster to keep cooler?

I finally was able to get my lighting system complete after veggin and somewhat flowering with 5 cfls. I bought a 250/400 mh/hps galaxy ballast. It is pretty good and got it for 25% off because of a lighting sale. I already had a cool tube waiting and got it all together. The cool tube is a bake round pyrex dish and a mogul socket, pretty cool design. Here is a picture of the cool tube setup.

http://www.picvalley.net/u/1653/62053831920028895661347256362CJr1n1XCJM45TqtXW8rV.JPG
image embedding isn't working so there is the link. ^

Basically its increased my temps by 2 Degrees F to about 86F.. not a big difference considering I am in the Sonoran desert and its been extremely hot lately. My room faces the sun and my A/C for my place stays around 80F and when sleeping I reduce to 78F. It is very expensive to run my A/C for the unit is 22 years old. So lowering my A/C is not really an option. My actual rooms ambient temperature runs anywhere from 81-84F. Depends if I have my door open and a house fan spreading the air out. My room only has one mesely vent that obviously isn't sufficient enough given the fact that my room faces the sun and should have had another vent added to the opposing side of the room. Basically I want to reduce my boxes temperatures as much as I can without adding an A/C unit.

Technical info of box.

2ft x 3.5 ft x 5ft
250w HPS Cool Tube
190 CFM inline exhaust fan 4" w/ carbon filter "pretty large carbon filter about 1.5ft tall and ft wide".
4 walmart 4" fans -- 7$ ones
2 plants one massive white widow plant and smaller mango kush.
Scrog technique being used
Soil/ FoxFarm/3 gallon pots
Air out-take hole is a 4" hole with dryer vent flaps.
Air intake is a 5.5" x 11" w/ a/c like cover

recently added another air intake right above the previous the exact same size to increase air flow.
I have two air intakes now both 5.5" x 11".

The addition of this new air intake has kept my temps below the 87F mark. Previously with one air intake it was getting to 88-90F.

The main problem I am having is that I am unable to seal my cool tube completely up. I have it not clamped on one side so it can pull air directly from the sides. Hard to explain but if you see the pic it is more clear. I also had once sealed up the holes I made for the wiring in the ducting and noticed this affected temps as well. I have now cut holes in the duct to allow air to pull through. The main problem now is that my carbon filter is pretty much not pullin air. I mean it is slightly but not efficiently since I have to leave the system open and can't fully seal it. I am devising a plan to make a boooster like fan directly to the right of my cool tube to flow air over the tube. With the previous design it was suppose to do this already but since sealing it increases temps im sacrificing filter for the time being. Smell is not an issue for I am a medical patient and my plants are not so smelly "yet" !!!

Here is a diagram of the box

http://desmond.imageshack.us/Himg717/scaled.php?server=717&filename=diagramr.jpg&res=landing

This should give you a better idea where my faults in my venting are "purposely made" to lower temps.

now for the main reason for this post. I plan on making a booster fan out of one of those 7$ 4" fans from walmart. They are pretty solid and should work well. All I want to do is get a nice breeze blowing through the cool tube. I plan on making some sort of box like thing out of some PVC parts and attaching it directly to the right end of the tube, then attaching duct to the booster. I don't really need a booster for my exhaust is good enough but I need a better air flow across the actual tube!? Its hard to explain but I hope with the amount of talking and pics I got someone can give me some good ideas on cooling this tube.

if your ambient temp is 81-84 your grow space will never get below that. No matter how big of a fan you have cooling your light.

The $7 walmart fans probably wont drop your temp at all.

after looking at your setup I dont get why you cut a hole in your ducting with a knife? And whats just laying inside the duct the cool tube?

Id get some high temp tape and do a layer around the cooltube ends then cable tie the duct to that. The tape will give you some thing to make a seal that will seat better then the glass itself. Id use cable ties over steel clamps to avoid cracking the glass. The 4" fan is more then enough to cool a 250w I use one to cool a 600w. But back to your high ambient temp, thats your biggest problem.

If running the ac cooler isnt a option id seal up your ducting/ cooltube, throw a exhale co2 bag in there and hope for the best. Ive had a few decent harvests running temps in the mid 80s before adding a ac.

Yeah I've came to the conclusion my ambient temp needs to be lower. Thank god summer is almost over fully. It sounds stupid that I cut the hole but trust me it had to be done. When I first set it up I did a dry run, I did not completely tape it all up and seal it. My temps stayed at 85F. The first initial holes were from the wiring. Once I sealed that up with duct tape and the other ends of the cool tube, the temp skyrocketed to 90F. I simply reversed what I did by poking holes like it initially had from the wiring. temps went back down to 85F-86F. thus my deductive reasoning . I was not about to leave it overnight at 90F. I have 20ft of extra ducting so it's not a problem. I just finished my booster and it has dropped it 2F. and sealed it up check it out now. Pretty cool and quick addition..

http://desmond.imageshack.us/Himg829/scaled.php?server=829&filename=img1044zs.jpg&res=landing

http://desmond.imageshack.us/Himg717/scaled.php?server=717&filename=img1045ke.jpg&res=landing

http://desmond.imageshack.us/Himg850/scaled.php?server=850&filename=img1043pc.jpg&res=landing