A little help with room size/filter and fan please.

Okay guys I have a room that is 5x5x6.5 and I have a Can-filter 9000 (4" Flange) and I am on a budget so I built a cheap ass fan for $40. I bought a 6" duct booster (rated for 250 CFM) and put a 6"-4" reducer on either end and duct taped it on the filter and used dryer vent (4") out of the room. It blows air only about 5' (length of the dryer vent) the air flow feels very weak out the other side but my door (B&W Poly) is drawn is so there is a negative pressure. By my calculations I only need 50CFM so should this be fine... I will post pics if need be. Thanks for the help.

also to note I have a 1000w light and growing 4 plants.

BUMP... Anyone???

THat booster fan will not be enough. Spend $150 on a 400 cfm inline fan and you will be more than happy. The heat from your light wll not be dispersed fast enough by that small fan. THose 6" are actually 150 cfm. They rate at 250cfm when they are hooked up to an air conditioning vent. If you are strapped for cash I have seen some things done with the stanley blower from walmart which only costs about $45. When you try to do this cheaply you end up spending more in the long run. The reason I say this is becuase I tried what you are doing already. It did not work at all. You can keep that fan and build a good bud dryer with it though.